I don’t know how this could happen.
In order to take out an FHA-insured HECM loan (Home Equity Conversion Mortgage, the most common kind of reverse mortgage) the youngest borrower
must be at least 62. The lender requires all owners to sign the mortgage application and note, and in fact, the age of the homeowners is critical in determining the amount of the loan. The older you are, the more you can borrow.
Before a reverse mortgage can be obtained, a full title search is always done on the home. If your name is on the title or deed, you will be listed as an owner. Perhaps the deed with your name on it was never recorded? I suggest you check the public records for your municipality to see how the deed is recorded. If your name appears, contact an attorney or the title company to have your name removed.