They keep calling my MOM'S cell phone!

Find out who they are, and send them a letter advising them to only contact you directly. Your mother should be able to do that on her own, though. She just needs to advise them they are calling on her cell phone, trying to reach you, and they need to stop. She could get their name and address and send it to them in writing as I'd be willing to bet my left arm they won't listen to your mother the first time. They'll probably wait a month, then call her cell phone again looking for you. That's why I would suggest she send it to them in writing, certified mail/return receipt requested.

Some CA's treat third parties as surrogate debtors, harassing and calling them constantly until the third party steps up and lets the CA know they aren't going to take it.

calling a cell phone is ILLEGAL, unless that number was given out for credit purposes.

I had someone call my next door neighbor looking for me. I am almost positive that it had to do with Capital One and the collectors who had the card at that point. She told them she didn't know who I was and they never called back. I would have certainly contacted the cretins had I known who they were. She said they would not give her a name or any other kind of information.