Fair Debt Collection Practice Violation? Information was given to a person not listed on the debt!?

I have a debt from an apartment complex from 6 years ago. It was a shared debt between my room mate and me. Both of our names are on the debt, but the collection agency has been speaking to his mother, wihtout my permission. They received permission from the other person, but NOT me. Is this a violation of some law, because they are calling me non-stop! and are very rude, as well as unethical. What are my options?