Refund of overpaid amount

I received our Vodacom account for the end of August. The total outstanding amount was R2862.22. I made my payment 28.8.2024 for the amount R8262.22. This was a mistake on my side. I immediately contact Vodacom. They informed me that I must send an email to the accounts department and send my account as well as the proof of payment and ask them to refund me the overpaid amount. On the 3rd of September I phoned Vodacom to follow up the refund. They confirmed that the letter was received and still within the time standard of 10-14 working days. I again phoned in on the 11 September to follow up the refund. I explain to the consultant that I urgently need the refund to settle other accounts. I was then transfer to his team leader and she said she will come back to me. This did not happen. Our account is still in credit with R5400 and now they are deducting it with the outstanding balance each month. I am very unhappy about this. IF your account is in arrear the just cut your account but if they owe you money you must wait and beg for a refund.