If they are bothering you, report them:

http://www.consumer.ftc.gov/articles/0149-debt-collection (Threatening civil proceedings with no intent to follow through, or threatening criminal process in order to collect a civil debt is a  violation of the Federal Fair Debt Collection Practices Act.)  The same goes for endless telephone harassment

Also contact your local attorney general

If they continue to bother you,  and you know you do not owe any money, tell them that you know this is  a debt scam and that you are making a complaint to the police for extortion.  Once you get a copy of the police report and they call you again , just read out the  file number and the name of the PD or Sheriff’s office involved.   Tell them you’ll be glad to send a copy to them at whatever address the jack***es are working out of now.

You'll probably have to yell at them and talk over them.
You have to get tuff with these people because,  being akin to thugs, brute force is (metaphorically speaking),  the only thing they understand.

Also, please read my entry concerning this Susan Fitz and her merry band of
debt scammers.  Well known scam artists.

"I'm not sure who this person is or how they were privy to so much of my personal information, including my family members' phone numbers, but I am extremely alarmed and terrified of how they were able to gain access to this information."

sep, that is very scary.

Same thing I feel a little better knowing that other people are getting the same message

These types of calls are from bottom feeders. At some point in your past you made a ghetto decision to let a bill default, maybe didn't pay an entire bill, default on a payday loan or cell phone bill. Your information was sold to a third party bottom feeder company who will continue to sell your information the rest of your life. Do not engage with these people!! Block their phone calls and explain the situation to your family members. Four years ago I actually called them back and once I got a hold of someone I asked them to email all of the details and I would share it with my lawyer, and if the debt were true and I did in fact owe it, then I would pay them. Well, after them telling me they would send the info, they never did!! They did however want my credit card info right then and there!! You are not going to get arrested and go to jail! If you have a true court case it will go to the courts!! It's not!! Do not engage and tell family members to not engage! Most people have new numbers anyways! They will not give the true info and they will steal your money and then start the harassing process all over again! Fill out a report on the Federal Trade Comission and local police and then relax!! Don't put to much info on this site either because they( bottom feeders) read these post as well! Don't let them scare you!! I told them I wish they would sue me just so I could know who they truly are, but they won't! It's a debt or maybe not! It may be just a scam! Do not give them money! Do not! It keeps them harassing people! Report all information! Voice mails now translate messages into script! I have it and I am forwarding it to the FTC!  Relax and don't engage!

You are correct! Scammers who have personal info! They get family meme era numbers fro the white pages!!