IRS requires an SSN to file in the IRS offshore streamlined amnesty program.
Since you have a SSN and SSN never expires, you’re ineligible to apply for ITIN.
You CANNOT Use IRS assigned IRSN instead of filing with SSN – ruled out by Q10 at https://www.irs.gov/individuals/international-taxpayers/streamlined-filing-compliance-procedures-for-u-s-taxpayers-residing-outside-the-united-states-frequently-asked-questions-and-answers
Try obtaining it from Niagara Falls SSA Toronto's "local" Social Security office at 540 Niagara Falls Blvd., Niagara Falls, NY 14304, 716-283-1066 (1-877-480-4992).
If obtaining it from Niagara Falls SSA cannot work, try mailing SSA a ‘lost card replacement’ request - comply with filing/documentation instructions that are different for Americans abroad (e.g., a drivers licence or other state issued identification or a US address).
See below details for different circumstances as in some instances to get an SSN one would need to appear in person with proof of US citizenship AND documentation showing that one was outside of the US for every 5 year period (if abroad from birth, then documentation since birth would be required) and for other instances it may suffice for one to fill in the paperwork in advance, bring proof of US citizenship (e.g., birth certificate) and provide the name and number of someone who could confirm how long one had lived outside the US.
U.S. citizens living abroad may apply for a first-time Social Security card or a replacement Social Security card at any Social Security Federal Benefits Unit (FBU) at designated U.S. embassies or consulates. The Social Security Administration (SSA) maintains a list of FBUs at www.ssa.gov/foreign/foreign.htm
An applicant for an original SSN who is under age 12 may apply by mail. The applicant can send the completed Social Security form SS-5 and required proofs (must be original documents or copies certified by the custodian of the record) to the servicing FBU. Applicants age 12 and older who have never had a SSN before must have an in-person interview.
All applicants for replacement cards may apply by mail. The same form is used for an original SSN or replacement card. The form asks for the SSN and other biographical information. If the SSN is unknown, SSA can search for the SSN with the biographical information. If no SSN is found, then SSA will send a letter stating that fact and ask the applicant to apply for an SSN.
If there is no SSA FBU at the U.S. embassy or consulate in the country where the U.S. citizen resides, the U.S. citizen may go to the consular section of the nearest U.S. embassy or consulate, which will accept the application and forward it to the SSA for adjudication.
In Europe, for example, there are SSA FBUs in U.S. embassies/consulate in the following jurisdictions (which also provide services for designated neighboring countries): Athens, Dublin, Frankfurt, Krakow, Lisbon, London, Paris, Rome, Madrid, Naples, Oslo, and Warsaw.
For a complete list of SSA FBUs abroad, see www.ssa.gov/foreign/foreign.htm.
Applicants will need an appointment, which they can make by email or phone call.
A person may inquire in person with a FBU to find out if he or she already has an SSN. The FBUs can provide the SSN in person if that person provides proper identification. The FBU cannot provide any written confirmation of the SSN other than a replacement SSN card. If the inquirer needs written proof of SSN, he or she must submit an application for a replacement SSN card. SSA is prohibited by law from disclosing the SSN by phone or letter, even to the number holder. Please note that this inquiry must be made directly to a FBU and cannot be made at a consular section of an embassy or consulate overseas that does not have a Federal Benefits Unit.
NOTE: Not all FBUs have access to SSA computer systems during all local business hours because of time zone differences and SSA systems being offline at night (Eastern Time) for updates and maintenance. People should call ahead to see if the FBU they wish to visit will have such access during their planned visit.
All applications for SSNs, whether original, replacement, or for change of name or other biographical data, use the same form, the SS-5 FS. There is no fee for this service. Page 2 of Form SS-5 FS provides the required evidence requirements for original and replacement Social Security cards. Also see https://www.ssa.gov/ssnumber/ss5doc.htm for information about documentation required.
In most cases, a full-validity, unexpired U.S. passport is sufficient proof of U.S. citizenship, age, and identity, but for purposes of an application for a Social Security card/number, it can only be used to establish any two of these three facts. A second document is required to prove the third fact. For example, if the U.S. passport is offered to establish U.S. citizenship and identity, another document, such as a birth certificate, would be needed to establish the age of the applicant.
The SSA may require additional documentation of identity if the U.S. citizen was born abroad to a U.S. citizen parent(s) and never lived in the United States, or was born or later naturalized in the United States but has lived abroad for most of his/her life.
An original foreign passport is acceptable for identification purposes but must be accompanied by proof of U.S. citizenship, such as a U.S. birth certificate, a full validity unexpired U.S. passport, a Consular Report of Birth Abroad of a U.S. Citizen (FS-240), or a Certificate of Citizenship (N-560/N-561). If the U.S. citizen naturalized, he/she may present a Certificate of Naturalization (N-550/N-570) or a Certificate of Citizenship (N-560/N-561) as proof of U.S citizenship.
The documentation must be comprehensive and dated from the time the person departed the United States to the present to provide sufficient evidence. The documentation can include: confirmation of residency from foreign registration offices;school records such as report cards or a letter from the school confirming dates of attendance;travel documents such as current or canceled passports (U.S. or other);employment records;medical records;proof of registration with a doctor or clinic.
Applicants must also submit documentation to show that they have never been assigned a SSN:
If the applicant lived outside the United States for an extended period, a current or previous passport, school and/or employment records, and any other record that would show long-term residence outside the United States could be used to show that the applicant does not have an SSN. If the applicant lived in the United States and is applying for an original Social Security number, the applicant may be asked for information about the schools they attended or to provide copies of tax records that would show they were never assigned an SSN.