Xiaomi S10T Robot Vacuum Does Not Enter Some Rooms and Carpets

I bought the Xiaomi S10T robot vacuum, but after the first use, I discovered that it is ineffective at cleaning. Despite precise mapping, it does not enter two of my rooms and does not reach certain carpets. I sent it to an authorized service twice, but they say there is no problem (which is odd). I purchased a new product that does not clean properly, but neither Media Markt nor Xiaomi provide a solution. They will not accept product returns. I have a map of unfinished cleaning. My opinion of the brand has shifted dramatically, and I want to return this item because the company does not stand behind its products. How could this happen with a brand-new product?