MTN & Mobiles Plus deliberate deception

I am appauled by the service I received from MTN and its sub contractor Mobiles Plus. Two months ago I ordered a phone, P20 Lite and instead I was given 2 wrong phones (P Smart), it would seem this was a calculated move to deceit me and sell me a false deal. I have since returned the two phones unopened ( the next day at an MTN store in Midrand) which was accepted and was given a collection reference. When I made a follow up with MTN a week later I was told to first raise the matter with Mobiles Plus who then responded by email as follows:

"We are happy to inform you that your query (157977) has been closed. If there is still any outstanding issues please do not hesitate to contact us." However I was surprised when I was billed end of July for this by MTN even though I returned the phones and I have prove. It's clear that both MTN and Mobiles Plus are in agreement and are used to taking advantage customers who chose to do deals over the phone instead of physical store visit, this way they are able to mislead them into false deals, with the intention of selling them redundant / unpopular products .