Refund a long process

I was contacted by old mutual to advise that I have refund due to me as I used to save with them This was 2 to 3 months ago They requested I send my docs through fax which I did and was never contacted again I then sent an email to complaints department they asked me to email and as long as I have an attachment the emails bounce back I told them this and they keep telling me to resend attachment 1 by 1 on different emails I did that but still it bounces back I am not sure what I am expected to do now because it's 3 months later and nothing still