i hate to sound like this but i am not sure if i would trust the legal companies even not to go after the full amount that is owed

many companies will not even work with you unless you default. i am sorry, i have just heard of this happening so many times, i know it is a hassle but i would really recommend securing your account. i had loans that i completly paid off on their terms, no default and they still cleaned out my account. also if you really have paid the illegeal companies, if you protect your account, you will not have to pay them anymore money.