Constant Problems with My Xiaomi Electric Scooter; No Returns Accepted

I purchased a Xiaomi electric scooter, and problems began after only 6 months. Constant malfunctions, we take it to the service center, they fix it for two days and then send it back, but as I previously stated, I can only use it for two days before the problem reappears. What kind of company does nothing to address the problems? Now I've been told that because I threw away my scooter's box at my old workplace, I can't send it in for warranty without the box, which they claim is an excuse. I demand an immediate response to my complaint, or I will take the matter elsewhere. I purchased the product from Media Markt, but they are not assisting me in this matter. I demand a replacement for my product under warranty; otherwise, I will file a lawsuit. A lawsuit will be filed in this case against the store where I purchased the product as well as the Xiaomi brand.