DMC Rotten

Debt Management services were paid a year ago and they never ever informed the credit bureaux of payment however they did send me a paid up letter at the time. I queried with them and the person answering the phone said there was nothing she could do for me. I called transunion and emailed all documents to them but to date DMC have not responded to them. This is still sitting on my credit report on 150+ days and unresolved. Not sure where to go from here. Some one please help