The State of Illinois has sued a debt collector alleging the debt collector used profanity, contacted people at work, and attempted to collect debts that were 20 years old!
I would say I am amazed by this, but alas, I am not. While this is definitely an extreme example, the concept is the same: debt collectors may use means that are in violation of state or federal law to collect a debt from you. Do not fall into their traps!