Two problems customer are issues ba

Two problems customer are issues back as much as possible.
My plan to solve:
1. The delay and Customer not have product will solve the problem by sending to FBA. (Sometimes customers are not Product because not at home.)
2. Customer return order because a small tshirt will solve by Attach the label T-shirt sizes people Asia and Europe, clearly.

I believe that this problem will be solved when the seller id are normal.