Data Issues

I recently took out a data contract with Axxess for 50GB + 50GB for R299. The last two months in a row, they've only loaded 40GB into my account and still made me pay the full amount without resolving the issue (The issue still hasn't been sorted out). Everytime i email them, they keep on saying they will sort it out, but the problem is still up there. Initially, I was quite pleased with their service, but now i'm really reconsidering my decision. I'm thinking of terminating my contract and possibly switching over to a new provider.