Poor Service and *********** stuff including store Manager

I went to cash crusaders today at Alberton to buy iPhone 11 Pro and my card was giving me problems,i told the cashier to put the phone aside for me I wanna sort out my debit card problem...I managed to sort it out and went back to the store within 10 minutes and the phone I asked to be put aside for me was being sold to someone else and the manager couldn't do anything about it. I wasn't treated fairly at all and I am angry...I wouldn't recommend cash crusaders to anyone to be honest they dont know how to treat customers