telkom ruining my credit life

In May 2017 I took out a data deal through Mondo a company outsourced by Telkom, once having received the sim card I realised it was not what we agreed upon I then called Mondo to cancel the contract on the basis of misrepresentation,after much hassle I received a message from Mondo notifying me of the contract cancellation, to my surprise, end of august Telkom debuted my account, I later reversed the transaction and subsequently I went back to enquire at mondo and they confirmed the cancellation in writing, end of September there was no debit but end if November there was another debit on my acc from Telkom,I went back to mondo and they assured me that the contract was cancelled and there was no reason for Telkom to still debit,the problem is that both mondo and Telkom tells me mondo needs to cancel the contract.