u/Animaloid

Hello guys, i have a little question.

So someone buyed a Lot of 10 cards from me. I counted and checked many times that i pack the right amount of cards before packing and everytime i counted to 10. So today he textet me that there are cards missing from tge Lot but i am 100% sure i sended him the right amount of cards. Is there anything i can/should do? The order is without trusteeservice btw.

Thank you!