I got a call from these goombas this morning (a Saturday no less). They sounded like angry cops, and were somewhat intimidating since they had my address and social. The call (perhaps coincidentally?) came minutes after I (stupidly and sleepily) applied to refinance my home through an app on my phone. I can't seem to find any record of that transaction but I know I did it...  ;-)  
They wanted to make an appointment to serve a summons, and I thought that didn't sound right.

Thanks for the info, glad to know I can ignore them.

You are correct, that's why they keep changing their phone number and refusing to answer any call backs because they know what they are doing is Illegal !!!
Point of interest to you, if the original company you owed the money to has written the money owed off as a bad debt, then they sold the debt to one of these Bill Collectors for pennies on the Dollar.  The original Company has written off the debt as a Bad Debt and taken advantage of the Income Loss on their Taxes !!!
The Debt Collector has just bought a bunch of bad debt from these firms, and the only way they can recoup their investment is by trying to squeeze, threaten, intimidate and etc. some money out of YOU !!!
Hang up on them once they have recognized who they are !!!
They have NO Legal standing with your Debt or their ability to collect it !!!
They are lower than scabs and they count on their intimidation of you as a way of trying to get you to feel threatened enough to send them some money !!!
Hang up on them immediately !!!
It's their LOSS, NOT yours !!!

"BILL COLLECTOR" Scam !!!
For me they were claiming to be with a Law Firm getting ready to file Court Documents on an account that I had back in the 80's ???
"Steinberg and Assoc." ???
They can't even come up with an original sounding name for the supposed Law Firm that they claimed to have been !!!
Actually, I kept them on the phone, playing question and answer games with them figuring that it was eating into their profits the longer I kept them on the line.
Then the call finally got so frustrated that he hung up on me !!!
I was fun though, because Bill Collector do not intimidate me with the threats of Legal Action or any other form of threatening actions, which are nothing more than threats with no teeth !!!
It was fun though, knowing that if I had just hung up on them, they would have immediately called someone else to harass them, so I just enjoyed playing with them and eating into their profit margin !!!

Omg then I shouldnt worry about going to court like they threatened! the guy said that I should take 1000 dollars to court with me and i only make 275 a month on ssi! I am so stressed from them right now its not funny they were so harrassing on the phone I could cry!

OMG they just called me today and threatened to take me to court for past debt. yes I owe it but they were rude. But I cant pay what they want me to pay so i hung up but i read its  illegal to threaten court unless you are a lawyer!

Got  a call from a Investigator Named Michael Lee, first claiming to be law enforcement and  claiming I owed money for a loan. This loan was included in a banrupcty 2 years ago. He said it had nothing to do with the bankrupcty. tried to gt 750 from me. he said there were 3 charges and they were gonna arrest me at work if i didnt pay this debt. Name of the company he said was ccs something...beware

they called me yesterday not only did they call me but they called my mother and sister in law... when i called them back i got a voicemail and demanded a proof of debt and reminded them that if a person was actually possibly facing court or criminal charges the server usually does not call the person that is going to be served before hand.. they just show up..

I had them call today.. not only did they call me but they called my mother in law and sister in law trying to contact me.. when i called them back all i received was a voicemail and i did the same thing you did... I demanded a proof of debt and reminded them that when and if a person is actually going to be taken to court the court server does not call ahead of time they just show up..

They are a scam claiming you owe them money for bad checks... and then stating they are thinking about an arrest.    I haven't written a personal check in over 10 years.  lol

I answered a BLOCKED call on my cell phone.  The called identifried himself as an investigator calling for my husband.  I ask what this call was regarding and he said he did not know but would transfer me to the accounting department.  They told me it was a "pay day loan" I said we have not taken out a payday loan or any loans.  He said they were trying to reach my husband to serve him a summons.  I ask him to send me a validation of this debt and he agreed but he only had time to email the validation because it was going to court.  I agreed.  Once I recieved this email it wasw not a validation of a debt but a settlement offer.  I called the number on the email and told them I needed a VALIDATION OF DEBT  not a SETTLEMENT OFFER.  He said that all that paperwork would be at the court house.  I said that I needed to see the actual contract in order to figure out what this was.  He said why don't you just pay it?  I said you want me to pay $1000 to a person calling without verification?  Anyway,  I replied to the email with a letter requesting validation of this debt and siting the Fair Debt Collection Practices Act.
They are a fraud!  
DO NOT SEND THEM ANYTHING!
You can find sample letters on the web to send these people.  They are in Jamestown,NY and seem very professional and act like the authorities until you refuse to pay them, then they are rude and hang up!