Poor Customer service, Erick and Zanele do not know/ understand the products

I have made purchases for a value of 24K on 16/10/24 at Prospection branch from a sales assistant Zanele who doesn't know the products she's selling as she sold me the incorrect fittings for my free standing bath. I went back and forth with her to have my products exchanged from collection to exchanging with the correct product. I then escalated the matter to Eric the store manager who also promised to compensate me with collection of the incorrect product that was sold to me. I then told him that i will rather come in store as i will be purchasing more products for my second bathroom towards month end and he agreed to give free delivery and exchange the wrong product that was sold to me by Zanele. When i got to the store Zanele exchanged the product for another one that costs R329 while Erick initially advised me that he will exchange it for another one that costs R700. Then i asked for the difference between the two products and they told me that the expensive one has a POP-UP while the other doesn't have. I then confirmed with Zanele if she included it on my previous sale so that i can take the cheaper one as they both do the same function and she told me that the POP-UP was sold to me so there is no need to buy it. Erick was convincing me to take the expensive one so that he can charge me on my sale hence if i took the cheaper one they will have to pay extra to cover up their mess. so i settled for the cheaper one, when i got home i then realized that a POP-UP was not included in my sale, it was in the other returned product [ which was incorrectly sold to me. I then called them back to request for the proof of payment as it was not given to me only to be told today that i was given for free this useless item worth R329 so i cannot take it back. they were fixing their mistake and still compensated me with a useless product as it doesn't have a POP-UP but now i am not allowed to return it. why not settle for another free product of the same value as this one is useless at the moment and i had to but the correct one elsewhere as i had already paid the plumber to start the project. I want to return this product and take something of the same value because now its their word against mine.