LTE sim only contract

I have a LTE sim only contract which I'd upgraded from a R199 to a R249 package. When I did the upgrade in the Hillcrest Kzn shop I was told to to a direct payment at Absa, then return to the shop with the receipt and they'd do the upgrade, which I duly did, being told the debit order would be changed for the following month. Then they put through an unauthorised debit through for an amiunt I didn't owe, which I had reversed after trying everything to get Telkom to sort it out. The following month I made a direct deposit not wanting the incorrect amount debited and informed Telkom of this. They again on just any date tried to take a much larger amount again, these transactions cost me high bank charge's. Eventually after getting a reply from Telkom to say they'll look into it and let me know. I receive an sms that I'm up to date and the case sorted out, I now get an invoice showing arrear's of R616 when I only owe R249 due tomorrow Telkom don't have any idea of what they're doing other than to try to rip me off, as I get a different amount each time they make contact eventually by e mail, sms and FB messenger