Billing for returned phone

I made an online application for an iPhone 14 in October, and the phone was delivered on the 17th October 2022. Before the phone was delivered, I called Vodacom inquiring about the phone size, I was worried that it may be small. The lady I spoke to told that on delivery if I'm not happy with the phone, I should call and return it. On the 18th October I called Vodacom and informed them that I was not happy with the phone size and would like to have it returned. The RAM courier services came to pick the phone up on at my workplace on the 19th October. On the 20th October I called Vodacom regarding the returned phone. Although they could see on the system that it was returned, they still had not received the phone. I was told to call again after a few days. I gave them the collection reference number which begins with 'COL' and numbers for them to check. I called again on the 27th October, the collection ref number was given again, they could see on the system that the phone was returned and it was going through some processing or something, but this was not finalised. When I called on the 27th, a transaction of just over R100 (prorata) had taken place from my account which I even complained about. The phone was returned and collected within 3 days (not beyond the mandatory 14 days period). On the 25th November Vodacom then debits my account an amount of R968.99- for the phone that they have in their possession, that was returned and fetched by the courier on the 19th October. I reversed the debit order. I tried calling Vodacom aftersales number which is forever busy because I needed someone to resolve this issue- but could not get through. This morning I get a notification from my bank, Vodacom has deducted R2038.36- for the phone that I do not have. I have been trying to make contact since morning, I cannot get through as their line is busy. I am at my wits' end- what am I paying for because the phone has been returned. My fear is that Vodacom will continue debiting my account even though I do not have the phone, OR they may have me blacklisted. It does not look like the returns office and the billing office talk to each other- how else does one explain billing for something that has been returned??????? UNACCEPTABLE