Well, sue them if you really have something actionable. Collectors still have room to be annoying without breaking laws.
If you are receiving repeated, misdirected, and/or abusive calls from a third party debt collector, you may find relief in the provisions of the FDCPA, the Federal law which regulates collector behavior and provides you simple tools for your own defense. It grants you control of how you are contacted, and collectors can be sued for their crimes. Learn your rights and first response tactics at FTC-dot-gov. See also your state laws for additional support.