Contract cancelation

I took up a contract with Mondo for a cellphone. The phone that I initially requested was listed around R880.00 a month. I received a call from one of their consultants who assistant me with the contract after everything was finalized I received an sms from MTN saying I would have to pay R1100 which was way more than my budget, so I decided to cancel the contract. I contact Mondo and was advised to take the phone back to any nearest MTN store and they will help with to fill documents and receive an IRMS number then once I've received the number I need to contact them to give the number so the can process the cancelation on their side. I did all of that on the 21.04.2023 and was advised it will take around 3 weeks to finalize everything. This is the 7th week and the contract has not been canceled, every time I need to contact Mondo for feedback and they always say they still waiting for feedback from DSV (after 7 weeks). While I'm waiting for this whole process MTN had tried to debit from my account they even said my account will be handed over to collections.

I don't think it's fair for me to pay for a devise that I did not even use let alone open and my credit record is being messed up. I can't even apply for another contract because of all of this.