You can't be "officially notified" via voice mail (or text, email, phone, for that matter).  Sounds like the typical scammer scenario - leave a threatening message in the hopes that it'll scare the called party enough so that they pay some bogus debt.  Report the call to the FTC, FBI, Dept of Justice and your state's Attorney General.

>> When I asked for a correspondence address, they refused for "personal" reasons <<

::snort:: That's a new one.  Glad you didn't fall for their (obvious) ruse; sadly, some people do.  Please do report it tho, and help get these crooks shut down.  

The Federal Trade Commission (FTC), the nation's consumer protection agency, is warning consumers to be on the alert for scam artists posing as debt collectors. It may be hard to tell the difference between a legitimate debt collector and a fake one. Sometimes a fake collector may even have some of your personal information, like a bank account number. A caller may be a fake debt collector if he:

is seeking payment on a debt for a loan you do not recognize;
refuses to give you a mailing address or phone number;
asks you for personal financial or sensitive information; or
exerts high pressure to try to scare you into paying, such as threatening to have you arrested or to report you to a law enforcement agency.




If you think that a caller may be a fake debt collector:

Ask the caller for his name, company, street address, and telephone number. Tell the caller that you refuse to discuss any debt until you get a written "validation notice." The notice must include the amount of the debt, the name of the creditor you owe, and your rights under the federal Fair Debt Collection Practices Act.

If a caller refuses to give you all of this information, do not pay! Paying a fake debt collector will not always make them go away. They may make up another debt to try to get more money from you.
Stop speaking with the caller. If you have the caller's address, send a letter demanding that the caller stop contacting you, and keep a copy for your files. By law, real debt collectors must stop calling you if you ask them to in writing.
Do not give the caller personal financial or other sensitive information. Never give out or confirm personal financial or other sensitive information like your bank account, credit card, or Social Security number unless you know whom you're dealing with. Scam artists, like fake debt collectors, can use your information to commit identity theft ? charging your existing credit cards, opening new credit card, checking, or savings accounts, writing fraudulent checks, or taking out loans in your name.
Contact your creditor. If the debt is legitimate ? but you think the collector may not be ? contact your creditor about the calls. Share the information you have about the suspicious calls and find out who, if anyone, the creditor has authorized to collect the debt.
Report the call. Contact the FTC and your state Attorney General's office with information about suspicious callers. Many states have their own debt collection laws in addition to the federal FDCPA. Your Attorney General's office can help you determine your rights under your state's law.

http://www.consumer.ftc.gov/articles/0258-fake-debt-collectors
http://www.consumerfraudreporting.org/reporting.php

Called  back to back with no caller ID stating they have a claim against me. When I informed them not to call me on that line, they refused to listen and said they were going to "serve" me legal papers. When asked for the full company name, they wouldn't give it to me. When I asked for a correspondence address, they refused for "personal" reasons....um, nothing about a company is personal.

I hate that they get away with this crap!

This number has been calling all of our cell phones repeatedly claiming to have "sealed documents" to serve us for a claim/charges that has been filed against us.  They asked for our address and date of birth and said when they arrived to "serve the sealed documents" that they would need 2 forms of identification.  The company they claim to represent is a company that we had done business with in the past, however, our balance was paid in full over a year ago.  I called the non-emergency number for our local police department, and they verified that this is a SCAM!  They said if someone does come to our door, DO NOT under any circumstances give them any identification, information or money.  They also said to call them back if someone shows up and they will send an officer out immediately.

THIS IS A SCAM!!!   They called and told me the same thing.  They said they would be delivering "sealed documents" and would need 2 forms of identification.   I called my local POLICE DEPARTMENT and they VERIFIED THIS IS A SCAM.  They said if someone comes to your door DO NOT GIVE them ANY IDENTIFICATION, INFORMATION OR MONEY!

Received a message from this # saying a claim has been filed against me and I have one chance to contact "Rick Masterson" before further legal action is taken. Ended the message by saying,'you have been officially notified'! What the H***???