Multiple Failures and Unjustified Charges for Roborock H7 Vacuum

About 1.5 months ago, my Roborock H7 vertical vacuum malfunctioned, and I sent it for service. After about a week, the service reported it fixed and returned it. However, after just a week of use, the vacuum began malfunctioning again in the same manner. We sent it back to the service. This time, approximately 15 days later, they claimed the previous repair was now a user error and demanded a fee of 5000 TL, and, as a gesture of "customer satisfaction," asked for 3000 TL from us. We requested detailed information about the alleged user error and indicated our refusal to pay the fee without clear information. However, they responded that they would return the product in damaged condition as we declined to pay the fee. The same issue occurred in the initial repair, and it wasn't a user error then, so how is it one now on the second occasion? Due to these approaches, we've been unable to use the product for about 2 months. I wish to express my complaint and distress on this matter. If a solution is not provided, we'll be forced to seek resolution through the Consumer Court.