Telkom contract gone bad

I lost my job and ended up being behind on my telkom contract acc. In April I got a new job and tried to make contact with telkom and at that time my arrears were about R7k. I was sent from pillar to post with no help even visited the telkom stores. In May I wanted to make a lumpsum payment but when I checked the emailed statement the balance had escalated to R23k. I contacted customer services and they told me it was interest and they can't do anything about it. I then sent an email requesting for the R13k interest to be reversed so I can make a R10k payment for the acc to be reinstated. Query Ref is ***. To this day, no one has gotten back to me and I don't know what else to do.