Disheartening

I ordered a MacBook Pro 13 inch M1 for my son, he’s working on heavy projects, his old laptop crashed, so we went to Rentoza as a solution and paid on the 2nd of June and on the 13th of June he called and said they delivered a MacBook Air which is +/-R1000 less than the pro I’m paying for. My son was tempted to use it and change the subscription but I told him to return it back to them so he did and that was on the 14th when they fetched it, he said they promised he’d have it by Friday this week. Friday has since passed as it is Sunday today, today is the 19th of June almost 17 days since I made my payment but yet we haven’t received the actual item we ordered. Note the next debit order will hit in a few days. So I’ll be two payments in on an item I haven’t received The issue here is the service and the shipping of a wrong item, how do you ship the wrong laptop? Please help.