How do I tell my overly defensive boyfriend that I feel unappreciated?

I've lend my boyfriend money to help him get on his feet. Each time he tells me he's going to pay me back, but when the time approaches when he says he'll give me the money he always says he doesn't have it all, or he still hasn't pay this bill or that bill, which tells me he can't afford to pay me. BUT recently he somehow had enough money to buy a galaxy tab and some other expensive stuff!! I feel used and I need to tell him, but I can't have a rational conversation with him because he is very defensive and finds ways to turns things around to make it seem like everything is my fault. If I talk to him he will probably say I am wrong for suggesting he has used me and then will get angry at me. What do I do?