No response after over a year of queries

I've been trying to get Old Mutual to help me with the transfer of my pension fund at a previous employer for years now, but their service has been absolutely terrible. Initially their team kept passing me around between consultants, but lately I haven't been getting any responses from them despite my requests.

I really don't know what to do anymore, clearly they don't care about me as a customer. I'm only using their services because it's part of the pension plan at the company I work for. If it wasn't for that I would have left them years ago.