Don't know what the laws are in the USA. In the UK if you buy a product and it's defective, your return it to the store, not the manufacturer. Your relationship/contract is with the store, not the manufacturer.

So take their advice and return it to the store.

If they refuse to offer a refund or exchange, you have support from your credit card company or PayPal.

Hobbywing make the best electronics available, so my advice is to buy another one once the refund is sorted. You won't find anything better.