Unhappy client

In 2021 after having agreed to a contract with MTN (Cresta Branch) for an iPhone 12 256GB, 6GB of data and 400 minutes of talk time for R789/month for 36 months I am still paying R1019. This was after numerous emails confirming what I wanted and signing the agreement for said amount. From the time of requesting the phone it took almost 3 months to eventually receive my phone. Subsequent to this I have raised many complaints to relevant departments within MTN which have also included the branch but to no avail and I continue to pay the R1019, more than 2 years down the line. I spoke to various people who made many empty promises but clearly this has all been brushed under the carpet as they are happy to be receiving an amount to which I did not agree. MTN blame the branch, the branch is not willing to accept any liability and this is how it has just been put aside. I will be very apprehensive about signing any further agreements with MTN once this contract is completed.