Miel..
I'm sooo sorry. These people are the worst I've seen yet. You're best bet is to try to work out a payment plan with them, better yet pay it off!!
You may want to freeze or close your account..I highly suggest one or the other. They will continue to attempt to hit it.
As for the law...well, they are not going by the United States law..they are located out of this country and we're still speculating on where their located.
Please, close your account and possibly change your phone number, try to make payment arrangments or pay them in full.
They are the worst of the worst and I'm sorry this has happened to you. But a lot of us got involved with these theives and this is what we have had to resort to...
Let us know how it goes...