Sales agent calling me a ****

I did an upgrade at Clearwater iStore at the end of March 2021, the agent Gift (***) informed me that the traded in handset will NO LONGER be charged to my contract of ***. The upgrade was done on line ***, and I was given absolute assurance that *** will have a zero charge for the forseeable future -- pertaining to the handset traded in. The next month I was billed on the handset which was traded in yet not in my possession and I made a query with Vodacom to note about the agreements made with Gift upon the assurance of the trade in previously. Since then, I have kept constant communication with the store (Gift) since Vodacom informed me to return to the store where the upgrade was done and the agent had been giving me an assurance that the matter would be resolved as he was seeking assistance from his colleague at the Vodacom store in the same mall. Upon requesting for the matter to be taken to a management level, I was called by Boitumelo in August who also mentioned that I was not supposed to have continued payment on the traded in device amid explanation of the matter at hand. Later I was emailed by Tebogo Senna, who I later found out was on the same level as Gift and had given me the same account as his colleague. I have an email from Gift where he stated that "the matter seems to be a mission" but they are getting to the bottom of it. This week the store came back with a different angle of my query, NOT addressing the issue, but touched on "overcharge" and "insurance", whereby the two items are not related to my long standing query. Today the store came back with links to terms and conditions, yet I had continuously questioned prior to taking up the trade in offer and furthermore was not lead to terms and conditions to be carefully read. Lerato from the store has cited that the agent responded to my query being "under the impression" that I am querying an overcharge. Are the agents working with assumptions or paying attention to detail at this store? For Lerato to say that Gift was "under the impression" clearly tells me that the staff is selling products to consumers WITHOUT a full understanding of the products being sold to consumers. That is very worrying and dangerous to the operation.