Telkom breaching their own Sales contract

Telkom went on a drive to move copper wire clients to fiber from a landline perspective. We accepted this offer in September 2021 which included a 10Mbs uncapped line. This was all contracted as per recording at R499/month, which included our existing landline number. Since then, they have charged me R799/month for almost 15 months now! After a myriad of complaints and logs (I have at least 8 reference numbers to prove it), I received an sms this morning that my account is now suspended due to non-payment! Although, I have been paying R550/month which is my monthly set debit order agreed on the same initial call contract. I have been bounced around between the Billing department and the Sales department so many times. I even engaged with Telkom's outsourced Contact Centre company who conclude the initial sale. However, Telkom and this company have a standard argument about who has the recording and why nobody wants to listen to it, as it represents the contract and is my protection as a consumer. I have no worries about leaving Telkom at this stage and they must just refund the R750 due to me. I also have multiple Telkom Mobile subscriptions which I will NOT renew. Lastly, I even wanted to take-on additional offers from Telkom but was refused due to my account being in arrears!