Closest thing to a return policy I could find on their site:
“What do I do if an item is received damaged?
If the item appears to have obvious shipping damage, immediately tell the UPS driver or USPS delivery person that you do not want to accept the package. If a package looks partially damaged, you can tell the driver to wait and open it to make sure the contents are not damaged If the damaged package was left or someone else signed for it, call UPS at 1-800-PICK-UPS (1800-742-5877) to report the damage or go to www.ups.com to submit a damaged shipment claim. Obtain a control number from UPS and email Common Sense RC customer service at sales@CommonSenseRC.com. We will file a damage claim on our side and keep track of the claim for you. Allow around 5-7 business days for the claim to be settled. Exchange or refund will be processed for you as quickly as possible.”
They also have a battery warranty registration link on their website but they dont have any guidelines for it so I am pretty confused too.