Media Markt Refuses Roborock Q7 Max Return

We purchased a Roborock Q7 Max robot vacuum from Media Markt on August 15, 2023, under the name u***, with invoice number SM02023000307610. Seven of us, including friends and ourselves, purchased the same brand and model of robot vacuum cleaner during the same week. We were pleased with the product and purchased one for my mother, who lives in another city. On August 25th, we delivered it to her, and it worked perfectly for the first two days. However, it abruptly stopped charging for a day and then resumed charging the following day. As a result, on September 3rd, it completely stopped charging for an entire day before restarting charging on its own. After about a week, it stopped charging completely and had difficulty finding its charging station, despite the fact that there were no obstacles. We decided to send it in for repairs, and on September 24th, we dropped it off at the service center, explaining the problems and requesting a replacement. When the product arrived at the service center, I called customer service and demanded a replacement. I explained that if a two-day-old product couldn't charge, it meant there was a manufacturing flaw, and I wouldn't accept a repair for a one-month-old product. If it could be repaired, the representative said they would fix it and return it. I refused to accept a product that had been repaired. We bought seven of the same robots at the same time and they all worked fine, so there's clearly a factory problem with the faulty one, and I won't accept anything less than a replacement.