Roborock Q7 Vacuum's Repeated Servicing and Denial of Refund

I bought a Roborock Q7 robot vacuum from the Bandrma Kipa branch, and it has already been sent three times to the service center. We asked for a refund, but it isn't being given. The staff at the branch didn't seem interested and weren't looking for ways to help. Even when we asked them to test it, they said no. They said it was a mistake on the part of the user without trying. They finally tested it after four days and found nothing wrong. They told us to come get it. Even though they don't look us in the eye, the employees are rude and don't talk to us well. We're stuck with a vacuum that doesn't work, and it seems like they don't care about our problems.