Sometimes toys keep vibrating (motor stays in the on position) if the batteries are put in the wrong way... it's a bit of an odd one but we've found that with several toys over the years - if you haven't already then please contact customer care who can test a product from our stock and get back to you to confirm if it's faulty and needs replacing. In the meantime do try the batteries the other way - just in case!
I second Bonny, my bullet is like that. If the battery is put wrong way in it just keeps going on the lowest setting. Some toys dont switch when batteries are put wrong, some can.
Just wanted to up date this post after contacting customer services. I was offered a replacement or because the product was out of stock a alternative. I did choose to wait because we really liked this toy.
Glad we did because the new one has been going fine so far no problems at all.