Poor service and robbing clients

Over the last 2 years, I have bought a lot of things from takealot. Recently, I have noticed that their service level is dropping. Recently, my mother bought me a gift for my birthday. I ended up getting a previously returned unit, which was faulty and could clearly be seen to be used. After a 2 week fight to return the unit, they credited her account, even though she wanted a refund, so we were forced to buy from them again. The latest incident and the one that this is mainly about is that I ordered a rowing machine. Paid the R200 extra surcharge that they enforce, only for them to deliver an exercise bike instead. Return the unit, requesting an exchange for the correct item. I am then told that if they have the correct item, I will receive it, if not they will credit my account. A few days later, even though their website and app show stock in both Cape Town and Joburg, I get told that they have no stock and credit my account. Minus the R200 surcharge. So not only am I out of pocket R200, but I didn't get the product that I asked for. This is unacceptable. I queried it and was told it has been escalated. I am still waiting almost a week later. Either refund me my full amount including the surcharge or give me the correct product!