Withholding my Pension contribution.

I have been waiting 27 weeks for my pension contribution to be paid out. Over 27 weeks, I have constantly phoned and emailed consultants only to be passed on from one consultant to the next. Ive been told, they never received my withdrawal documents and when I forward the sent emails, I dont get a response. I have spoken to their Senior Consultants and every time I get through Im being Promised to receive feedback but nothing happens! Every past employee I know has had the same problem with NMG. They over promise and Under delivery, in this case Im being totally ignored and they are withholding my money without explanation.