877-386-5224

I called it and was threatened by a recorded message to call them or else.
I called again and got a man who asked if I was Herbert Joseph then got offended when I asked why he was calling me (not Herbert Joseph) a real jerk.

Called number back and they claim that Derek Wilson is an "associate" of my husband.  We have never heard of a Derek Wilson.  They said that they will never call back but I'm sure they will until I threaten to call the FCC on them several times, which I will do.

I been getting harassing phone calls from this number, saying they need to talk to my daughter for a claim. When I called them back and asked who they were, they said they were from the Np group. My daughter has never heard of them.

Looks like these guys. Fake debt collector scam https://800notes.com/Phone.aspx/1-877-871-3919/3

telling me i own money on a payday loan i never did saying pay now!!!

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 you, but then says you could avoid it by calling another number

Federal law (FDCPA) requires them to send you a letter (US MAIL ONLY) 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

the caller id showed (877) 372-2597 but in the voice mail left, they say to call back the (877) 386-5224 number. What concerns me is that the name referenced in the voice mail is a friend of mine. I don't like that these scammers got my phone number in connection to my friend's name. Message said they are trying to find my friend through location and tracing efforts and I need to call them back if I know their whereabouts. I am obviously not going to return the call but I am warning my friend now.

I had the exact same thing as jm above, however, the phone I have is a work cell phone not a personal phone.  I did call back both numbers; no one answered the 877-386-5224 number but when I called the 877-372-2597 number it went to voicemail.

I got a call yesterday from 877-372-2597 at 1:38 PM (left no voicemail), called number back and company is NP Group (or maybe MP Group).  Rcvd call today 12/22/2015 from 877-372-2597 with a "Threatened" recorded message stating to call back 877-372-2597. I called from google voice number and Miss Mobley answered, and would not give out name of company calling...she stated my number was not in her system and couldn't disclose company name.  Sounds Fishy to me.