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.ftc.gov/bcp/edu/pubs/consumer/alerts/alt076.shtm

PS--You can also file a complaint with Lisa Madigan, the AG in Illinois. She is a champion of consumer issues and a Rotweiler towards unruly debt collectors:

http://illinoisattorneygeneral.gov/about/contacts.html

These people have been harassing my parents while my mother is extremely ill, going through chemo therapy. She called me in tears last night because they called her and told her I had two warrants out for my arrest, and if I didn't show up for court today I would have another warrant. How exactly can I go about filing a complaint against them in Illinois?

I received a call from these people this morning. they said it was for writing bad checks.  

first off they county attorney's office would be the one who serves said documents not a collection agency. they suggested i call the 877-630-1680 number to resolve the issue.  they then proceeded to give me a "case number" which is a reference number since the city/county i live in does not have case numbers such as the one the lady gave me. i have filed a complaint with the FBI for scam and contacted the State District Attorney's office for their continuous calling.

This is a collection company who is prey on people who owe a debt, they call your folks, your friends and you stating they are a 'county processor' or 'private processor' that are locating you to serve you with a summons, and if you would like to resolve this problem, call 877-630-1680.  If this happens to you, Forward this information to the State District Attorney, and tell them a) you know they are practicing criminal collection tactics and that you forwardeded it, or tell them sure, come serve me, and they wont show.

Their sole objective is to get you to call the 877#  to pay a debt that usually is manytimes inflated the actual debt.  Also, the 877# changes constantly.