Stolen credit card details? How do they buy stuff with them?

The scammers are pros. They have idiots in the US get the merchandise and then forward it to them in their 3rd world country.

Those idiots are just morons, not criminals.

The often pretend to be in love with some 300 pounder to get them to do this stuff.

The banks don't trace the shipping addresses when the purchases are made. If someone orders something shipped to somewhere that isn't the cardholder's address, they just assume it is a gift being sent to a friend or relative at that address.

The thieves don't use their own addresses. They use other addresses, pick up the purchases before the banks find out that the cc details were stolen, and don't return to the addresses again. When the bank finds out that the cc details were stolen, it's too late for tracing the address to do any good, because the thief and the purchase are already gone.