They can not:
call you repeatedly
call you at inconvenient times
accuse you of committing a crime
use deceptive practices to get you to pay
call and use your information with other 3rd parties against you
Make sure you know you're rights. Get all the details and let those collectors know that you are not going to take it any more. You should find out how to stop those harrassing calls. Did you know that some collectors make up fake debt? Do not pay for debts you do not owe. Arm yourself with knowledge. You will not be taken advantage of or made to feel bad ever again.
Find out your rights and what the Fair Debt Collection Practices says by doing your research. Your knowledge about your rights will help you when speaking with the collectors every time they call or try to contact you. Stop those collection harassments before they get out of control. Let them know you know what they can and can’t do and you will be listening carefully to what they have to say. It will make them think twice about coming after you in ways they are not allowed too!