What if my boyfriend borrows money and doesn't pay it back?

If you don't plan to associate with him again, then you must be careful and try to collect some evidence, which should be easy to get, such as finding out where the money is going, or trying to set some by SMS. In fact, if you really go to court, he is guilty of indefensible, and you will definitely get the money back. You don't have to go to court. After all, you were once lovers. Let's be free and easy. If he is really that kind of hooligan, you don't have to think much about him. Such people are not worth wasting your breath!