Calling all the time on my cell. I picked up one day and she verified my name and then said for me to hold for a supervisor. I hung up. Other times they leave a voice mail that I can't understand or when I can they leave a number to be referenced when I call back.
I have no outstanding debt. The called id comes up as unknown.

Called my workplace, gave two numbers to call back: 1-800-716-1618 and 1-800-448-9570. Would never leave a message at first and called over and over again, disturbing my co-workers.  Finally left a message for me to call Ronald (my co-worker couldn't understand the last name and might even have gotten the first name wrong) with an extension of 4655.  They called again the same day, when I was around to answer. A man asked my name and then transferred me to someone else. I was on hold for a while when a rude lady eventually came on the line. She told me that I owed money but was very vague about the whole thing. I told her the number she was calling was a work number and she was tying it up/disturbing my place of work (this is true - she was calling our public number that is quite busy).  She got upset and said I had to deal with this, that they would garnish my wages if I ignored her. I told her not to call back ever again and hung up. They called back the next day.  
I think they said they are NCO Financial, but they talk so fast, it's hard to say for sure. Also, sometimes the number they call from is an Ohio number.

Says they are ACL Financial attempting to collect a debt WTH??? Call ALL the time , number shows up as unknown this is my cell

David Miller of 800-716-1618 called my employer, HARASSED the secretary to give him my home phone. Calls OFTEN, leaves messages on machine NOT saying WHO he is calling for nor WHAT he is calling regarding, and calls at LATE hour.

Call again and DIE!!!

I got a v-mail from 800-448-9570  but asked to call 800-716-1618.  I made the call 2 days later to the 1st number, the woman xferred me to an automated machine. I hang up and called the 2nd number. Spoke to a live person, he asked for my SSN. I didn't give and asked what was the called about.  He requested my name.  He didn't get that either but did ask if the phone number I was calling from so he could check his record. It's shown on his caller id, I guess.  So he went silence for a second and then asked for my name again.  I requested him what the record shows.  He asked if my name was Jacob Michelle.  I said no and requested him to remove my number from his record or I will report him/agency to the Bureau of Consumer. The line went dead.

same thing happened to me

They call my land line several times a week..........who knows they are debt scavengers?

Received two voice-mails from this number. Automated caller using a very bad recording of woman with no vocal skill, and she didn't identify the name of the company calling; just said to call back 'Mr Armstrong at 1-800-716-1618'.

The Budd Hibbs site says that it is the OSI division of NCO Financial.

Left a message that they are calling from ACL Financial Systems about collecting a debt.  Said to call 800-716-1618 extension 5612.  They did not say who owes the debt or what the debt is.  No one in this house has any debt.

Calls my cell phone. Have no clue how the cell number was discovered.
Could the "Do not call" registration site be to blame for this?
Leaves message identifying themselves as "NCI Financial". Never heard of them.

please call Tina Smith at 1 800 716 1618 ex 5003.They call all hours even on Sundays, not identifying what company they are from or what the purpose of the call is when they leave a voice message.Never heard of them untill I found this site.Now I know better.Will report them.

Here's all the dirt on OSI and advice on dealing with them: http://www.budhibbs.com/debtcollectorpages/osi_outsourcing_solutions.htm

The thing that cracks me up is that while harassing people about paying their alleged bills, OSI went into bankruptcy to protect themselves against their creditors lol!

It's a collection agency "OSI Education Services, Inc." OSI stands for "Outsourcing Solutions Inc."