TRIVOICE INTERNATIONAL, LTD. Unautorized charges on the AT&T Phone bill Internet

My Mom and Dads combined bill from AT&T was unusually high last month so they asked me to look at it. While verifying the charges I noticed an unusual entry for a voice mail service. I inquired and found that mom & dad did not sign up nor did they have any idea what this was.

I continued to investigate further and found that they have been charged $14.95 per month since September 2007 for a service they neither use or need. Oh, did I mention that Mom & Dad still use an answering machine?! I called AT&T and informed them of the situation and they were as helpful as they could be. They removed the charges for the current month and put in an instruction to remove the 3rd party service from the account.

The one problem I need assistance with is since they pay their AT&T bill the old fashioned way, with a check; could you advise me on how we can go about getting their money back. Irealize that I will have to call Trivoice first, I am refering to what might be my next step. Since I think the company is not going to want to come off of a little over $500.