For many months, I got phone calls telling me I was responsible for paying a debt that my aunt had incurred and didn't pay. She'd put me down as co-signer. I was about 20 at the time of the calls. They threatened to put me in jail, ruin my credit, you name it. The last call, I asked when the loan was taken out and at the time, I was 14. So, of course, that made it illegal.
Go to the jewelry store and look at the signature. That should be an end to it. Hope it works out.
Hugs