what can i do about an online shoe company that has ripped me off?

my son ordered a pair of shoes from ';all the hot kicks'; and we havent rec'd them. i have emailed them several times. They eventually email me back but all they tell me is they are checking into my order. i keep threatening to do something about it but i really dont know what to do. They repeatedly just tell me that i should have gotten the shoes by now but they are checking into my order. What can i do?/