Vodacom New Market, Alberton Coerced and took my iphone and replaced it with Vivo

Vodacom is refusing to give me my phone back. I have an active contract (iphone 14) and insurance with Vodacom. My phone had a speaker (haptic) problem and i took it to Vodacom, New Market in Alberton to check what the problem might be. Just by looking at the phone, without any technical assessment the salesperson said the phone need to be replaced. They gave me option of iphone 15 as the iphone 14 is no longer in stock. Before even making a decision the salesperson called an agent representing Vivo to come sell and convince me to replace with Vivo. They said all the good thing about the phone and pressured me to take the phone without an opportunity to think, research the phone and time to process everything. I took the phone and left the store only to realise that the Vivo phone they gave me is a very low quality phone with poor functionality. I immediately called the salesperson the following day to return the phone and either be given my phone (iphone 14) or replaced my phone with similar phone. Both the salesperson and the store manager refused saying i have already put my simcard into the Vivo and they can’t take it back. I left the phone in the store since i cant use the phone, and the manager was very rude telling me that the phone is now regarded as used and therefore cant take it back. Note with all that happened I have not received any documentation confirming that I was given the Vivo, the only thing are some paper signed in the store with the advice of the salesperson. Im now left without a phone as they couldn’t even give me the loan phone in the meantime. All I need is my phone back as im currently on contract paying @R1300 pm for the phone i don’t even have. I also paid R1800 in store. Please help resolve this ASAP