Customer wanting me to pay a crazy amount for shipping I already paid

[brda_8454]

Customer says the usps gave him a bill for 54$ to cover shipping fees which I already payed and shipped item was 25$ the shipping was 7$ something he says they want 54$ to cover shipping 

[disneyshopper]

You are not required to pay any more than what the listing displays.  If the seller made a mistake, he is responsible for paying the difference.  What is the item number?  Wondering how the seller could have made such an error when submitting the weight and dimensions of the package.

[brda_8454]

I’m the seller the buyer says that the usps says he has to pay 54 more dollars to receive package I paid for shipping already like 7 or 8 dollars it weighed less than 2 lbs so how could shipping possibly be that much for shipping in the us from wv to Nevada it’s impossible I think either post office made a mistake or I got  scammed