Pension fund : not following instructions

Waiting 2 months for pension payout after resignation. I resigned and my employer send instructions to the fund. When I enquire their response is they did not receive it even after sendinf them PROOF ! They dont answer emails and on contact number only response is "they did not receive it" and will not durther investigate even after sending proof of emails send. Can somebody advise what ro do if the fund will not action instructions after 2 monrhs?!