I have been waiting for a D180 form to be signed f...

I have been waiting for a D180 form to be signed for months. I have tried to call several times, no reply, and I decided to send the cheque they ask you to send in order for the judge to sign the certificate, they took the money a month ago and I still have not received the certificate. Very unhelpful!!! I do not even know how to complain formally. Anyone knows?