Buyer returned used phone

We sold a brand new $1500 cell phone here on Amazon. Buyer returned it for "Inaccurate website description" which was false. They had it for nearly 3 weeks before returning. Buy anyways buyer returned it used and not new like Amazon return policy it musts be for a cell phone return. I am coming here asking for advice from Mods to see if we should issue a small partial refund or charge the full 100% restocking fee. We do not sell or carry used phone as we don't want to sell a subpar product and we dont have the proper team in place to grade a phone in A, B, C conditions. Appreciate any positive feedback, thank you.

Amazon return policy: This item can be returned in its original condition for a full refund or replacement within 30 days of receipt. You may receive a partial or no refund on used, damaged or materially different returns.

Item was sold in: NEW, SEALED