Vodacom :(

I bought a Samsung A12 on the 9th of Sept at CelluCity. 8 days later it started having wierd lines on the screen. I took it to Vodacom Greenaces as 7 days for an exchange had passed. Vodacom kept the phone for a further almost 2 weeks, yesterday they smsd that it has water damage on the sim tray and I had to pay R1100. I never touched the sim tray, the sim was inserted instore when I was buying it. When I went to book the phone in I asked the consultant to have a look as there was no physical damage like falling or Mark's. Vodacom had the phone longer than I did and If any damage happened it must've happened at their premises. I called the store a very rude consultant answered and I asked for the manager. I really hate Vodacom and my current provider is Vodacom. I want absolutely nothing bt they can take their phone and give me my refund, I used payjoy. An instalment is due bt already have an amount of R1100. This is disgusting