Need Collections Advice in Michigan

[Lanetta]

What is the name of your state? Michigan

In 2005 my son was contacted by an Atty who is collecting on a debt he owed to Sears. We asked for verification of the debt. He did owe money to them, but couldn't pay when he went to Jail for a year on a DUI. So he is willing to clear this up as well as a couple others. A letter was sent indicating he would make payments of _______ each month and more when he could. Each month the checks were accepted and a new statement was mailed out. Until 01/05/07 when the balances were not jiving anymore. Two letters were sent asking for an explanation with no response other than a new statement that still did not jive. A third letter was sent in which I stated that no more payments would be sent unless the discrepancy was cleared up. Now I get a statement showing that she charged $45 costs on 01/05/07, a $20 motion fee on 02/21/07 and 13% interest beginning on 020807. Can they legally do this this without notice?What is the name of your state?