I know someone who cancelled their Motability car less than 1 month after having it. The car had done less than 500 miles. They called motability customer service and explained why it was not fit for purpose and Motability agreed for it to be returned. They got their AP returned (done on a pro rata basis I believe). Any additional extras you might have added, will not be refunded. Motability only allow a couple of cancellations every 3 years so make sure your next car meets your requirements. All the best,