Telkom credit never refunded

Telkom owes me a credit refund since April 2022. I had to cancel my account with them as they could not move my ads line as my new address does not exist on their system. Then I had to pay, an amount, and when receiving my final invoice it was in a credit of almost R400, which I didn't receive until today. I had to send my proof of bank account for 3months that I haven't received the payment, as their system said the refund was made. I've phoned numerous times, and everytime spend about 45min on a call, I also email with a query, I was advised that it's referred to a manager or something but still nothing.... if you owe them money they will quickly disconnect or sue.... but if they owe you... that's a whole different story!!!