Telkom is a their

hello Peter, I hava a problem with Telkom cancellation, last invoice sent to me was final invoice because I cancelled all my contracts but this morning I received an email saying that I owe them money. I have been trying to cancel my contract since the end of February 2024, last month said the contract was cancelled and the final invoice was sent to my surprise now they sent me a new invoice but the accounts are all deactivated. I don’t know what to do with them now, can you please help me. next thing they will be handing me over to the lawyers and dragging down my name.