This is a common ploy by criminals masquerading as debt collectors who are attempting to extort money from people by scaring you into believing that you will be criminally charged, go to jail, lose your driver’s license, have wages garnished, be sued, and a variety of other variations on this, all for an alleged or nonexistent debt. One of the tricks they use is to call your work place, friends, or relatives repeatedly in an attempt to shame you into paying. They also use the “process server” ruse who calls and claims he is going to serve
Tell them they can have it one of 2 ways. They can go ahead and sue you, in which case you will be filing a counter suit for FDCPA violations, which you will win and they will be paying you, or they can follow the letter of the law and send you this dunning letter and you will then make them validate the debt:
Federal law (FDCPA) requires them to send you a letter (US MAIL ONLY) postmarked within 5 days of their first contact that contains their name, physical address, the creditor’s name, and the amount of the alleged debt. It also must contains “mini-Miranda” telling you that it is an attempt to collect a debt and that all information will be used for those purposes. The one other important thing that this letter must also have in it is that you have a right to dispute the debt within 30 days of receipt of the letter and if you do so, all collection activity must be stopped until the debt is verified.
Read up on your rights here, get template letters to send and also make a complaint at this government site: http://www.consumerfinance.gov/
Also file a complaint with your State Attorney General's office.
List of State AG’s offices: http://consumerfraudreporting.org/stateattorneygenerallist.php