Cavalry Portfolio Services And Sprint RIPOFF attempting to obtain bill payment for for non-existent service Tempe Arizona

My mother, who is a partially disable woman in her seventies living alone in Duluth, MN, has been harrassed for nearly two years by Sprint, and now Cavalry, for a Sprint bill that she could not have owed. She has been sent recent collection letters for a sum of $507.65 by Cavalry. I had had dirct phone conversations with Sprint about a year ago, where they agreed that the bill was not hers. Somehow she had originally gotten billed by Sprint for charges incurred by someone with her same name in Florida. She has never been to Florida, nor has she ever had a Sprint PCS account. Either Sprint was confused, or there was identity theft involved.

Regardless, based on my mothers age and location, Sprint had agreed on the phone that the person owing the bill was not her and the bills stopped temporarily. Now nearly a year later the bills are coming in again, but from Calvary Portfolio Services. My mother has never recieved any original bills from either company to prove that the bills were or were not hers.

Cavalry states in their collection form that copies of original billing information would be forwarded upon request, yet I have written to both Cavalry and Sprint twice in as many months, with neither providing the information requested.

Yesterday my mother contacted me again all upset, because Cavalry has sent her forms requesting that she provide all her personal information including copies of utility bills, her social security number, etc. I told her to not provide her personal information at this time, with the fear that they will use this information and re-incorporate it into earlier bill information. I may just be paranoid, but excuse me for not trusting people asking for money that you do not owe. My mother also stated that she has gotten a ding on her credit card report that she feels was introduced by Cavalry.

I have been trying to do what I can for her long distance, as she is extremely emotionally distressed by this whole situation, and cannot research this herself. Is there any free local legal advice that she can obtain in Duluth, MN to close out this problem?
Can anyone give any advice?

Randy
Rochester, MN, Minnesota
U.S.A.