Being told to pay R1300 to repair a part on the machine that is still under warranty!!!

I bought the Karcher wet and dry vacuum cleaner from the Sunward park lifestyle centre on the26th of March 2020. A month later the machine started smelling like it was burning. We stopped using it because we didn’t want it getting worse. We then returned it end of May/ beginning of June to get it checked out because it is still Very much under warranty. We then got a call saying that We need to pay R1 300 to get the machine repaired, i made it clear that i will not pay the price of a new machine to get mine fixed. They said they would get back to me with feedback. We waited and then after a month of waiting we get told that we are at fault because we didn’t use the machine with the filter on. I still don’t understand because when the machine was returned everything was still in tact,a month later we are told that the machine being damaged is our fault and are told that they even have pictures. Why was this not disclosed the first day it was taken in??? I have never been so disappointed in my life, we buy a machine and it gives us issues then we are told to basically pay the price of a new machine to get the old one repaired. Is this a joke??? I just need my money to be refunded because it is evident that they are not willing to fix the machine. If there was a no star rating at all. I would choose that option. Why say a product has warranty then tell customers that they need to pay when it gives them problems?