Bests & Worsts Reviews from Amazon

I got this bike at the end of May. I loved it! So fun! It just really made me smile. I rode it every chance I could. On July 4 I rode the bike. When I was through, I charged the battery and put the bike away in the shed. The next day, the motor didn't work. I have tried to work with the seller. I the bike checked by a repairman. I cannot get it fixed. Now, when asked for a refund, the seller said I had to ship them the bike in the original packaging before they will return my money! Who keeps a huge cardboard box for 6 weeks?? I am so upset! I feel cheated . I hope Amazon customer service steps in to help. Because this seller does not seem like they are going to make things right.