Telkom is working on my nerves

I have cancelled our contract with Telkom on the 22nd of January debit order still went off in March? I cancelled the debit order on my Cheque card and now there's an amount of Telkom that went of on my credit card on the 6th of April? Please explain how that happened because now I have to pay interest fee of my credit card and I will send you a statement if you dont believe me. Please sort this out urgently or this situation will go further ref nr of my call in January Ntokozo 22 Jan 1819. I phoned again 2 days ago and one of the consultants said that he is writing an email to the manager to contact me NO ONE PHONE ME AS YET. This morning 2.45am another amount was debited off my account. I demand that my money get paid back and my interest that went of my credit card as well.