Bad service

I am so disappointed at the service I received from vodacom. They are failing to assist me with a paid up letter for my account which ended end of August. I have been contacting them since then and they always promise to send but I receive nothing!!! Yesterday I was suddenly informed of an amount I did not know off and paid it just to get the letter. However, I am still not getting any help. When I visit the branch I am told I should call direct.