My mother got a visit from a sales representative,...

My mother got a visit from a sales representative, fast sales and mobility scooter goes 15km per hour. Is new model and is not yet in the brochure. Delivered and what appears to be a bad battery, so new battery in it. Now my mother is driving and what was she happy to be mobile but 8km is his top, we call and submit the complaint. Answer trade-in period has expired, wrong information is not included and can pay 700 euros otherwise there is no option. So you pay 3,000 euros for a bad buy and can pay even more to compensate for their mistake, I am now going to take legal action for my mother