Poor service for returned product

I ordered a laptop online in January 2022. When it arrived, it was not the deal I had requested. I delivered it to the nearest branch and they provided me with an IRMS number for return to the warehouse. I called it through to MTN as instructed, and assumed all was well. However, my account was sent and payments deducted for the laptop. I called MTN numerous times and spoke to different call center agents and was informed the laptop was returned to the warehouse, and my account would be credited accordingly. This however did not happen. I kept on contacting them and been assured it would be rectified. Suddenly towards the end of June i receive an email stating they had been trying to call me (no calls were received from them) and the laptop had never been received by the warehouse. I have contacted the store where I returned it, and they have assured me that the laptop was sent to the warehouse. This after numerous messages and phonecalls. Then on the 22/07/2022 I receive an email from MTN stating that " Your device was rejected by the warehouse and the package was sent back to the store. Please rebook the device and provide us with a new IRMS number." How do I rebook the laptop when I have not had it in my possession since 02/02/2022? And the Beacon Bay branch is adamant that they sent it off with the courier? I am fed up with MTN and it's poor service, as they continue to take payment for a product I returned!!! Please advise. The tell sales people should also be accountable for the products they sell to the customer. Explain in full details what is been sold.