Bad service from MTN

I was due for an upgrade in June and having received deals from MTN. I chose one for Samsung S23 with a free smar****ch. I got a call to confirm my choice and the sales person then said I could also get earbuds for free. On receipt of the invoice I notice that I had been charged for the smar****ch. I immediately called customer care to report this. I was put through to Mondo who it seems are responsible for MTN’s deals and they confirmed the deal I had signed for was not the one delivered and they suggested I them cancel the deal by returning the devices. This I did on 05/07/2023 on IRMS***-1. I have been following up daily with both Mondo and MTN as they keep charging me for devices I no longer have. They’ve shuttled me from Pilar to post about the devices not having been received at the warehouse for the cancellation to be effected. I followed up this morning with Mondo telling me that they sent through the confirmation of receipt on the 21st to MTN and the later refusing receipt of the same. MTN has subsequently refused to do the cancellation and redo the deal. I have been with MTN for over 15years