Dololo Paid up letter for months

I was under debt review and the debt review company was handling my account with Wonga. I have settled my Wonga account for months now. The debt review company has been asking Wonga for a paid ever since but they not getting any joy from Wonga. I tried calling Wonga myself but my call is redirected to a collections company. This is frustrating and it seems there is nothing I can do because I can't get hold of them.