Incorrect subscription charge

I changed my fibre package from R699 (20mb) to R449 (25mb) 2 months ago. I was paying the old rates, when the new packages were cheaper. The new billing was fine for the 1st month, and then it went back to R699. Sales dept. changed it back to 25mbs but my billing is still incorrect. I called the billing dept and they said a fault has been logged and I must wait for them to call me. Logged a fault, and I get calls but keep getting cut off. Really struggling with Telkom right now.