Telkom handing me over for "debt" that has been paid

In December, Telkom did not process my debit order for my account. I then went in to find out why, and the assistant advised me that he was not sure why the debit order had not gone off and that it potentially would go off later that day. He also said that if it didn't go off later that day, I should go make a payment at another store as they do not accept payments. A couple of days passed without the automatic payment being processed, so I proceeded to make the payment for the outstanding amount. (My billing date is the 5th of each month, therefore, the statement will reflect amounts due for the subsequent month in addition to the current month's dues.) On the morning of December 20th, I received a notification indicating that the entire balance, including the portion not due until January 5th, had been withdrawn from my account, despite my account being in good standing. Consequently, I visited my bank and successfully reversed the payment. On January 5th, the debit order was processed, and in the afternoon, I received a text message indicating the possibility of legal action to recover the amounts paid in December and January. We promptly visited Telkom to inquire about the situation. They provided a contact number, which proved ineffective. Consequently, we requested them to make the call on our behalf. Both the billing and sales departments confirmed that my account was in good standing and advised me to disregard the SMS. Since then, I have been the recipient of numerous SMS messages containing threats of legal action and demands for payment of debts that have already been settled. The specific dates mentioned in these messages are as follows: 11th, 15th, 18th, 24th, 31st of January, and 2nd of February. I find it deeply concerning that, despite my consistent efforts to maintain an up-to-date account and fulfill all financial obligations, I am being subjected to such harassment. It is imperative that this matter be addressed promptly to rectify the situation and restore my confidence in the company's customer service practices