They change their name frequently to avoid the many lawsuits and actions being taken against them by state and federal agencies.

I think the principal entity is this company:

http://cmassociationgroup.blogspot.com/

Pamela Cummings Mathews was running that group as well as a newer front that opened last year in Anaheim CA known as PB Recoveries.

Ironically Pam Mathews and a few of her "colleagues" are currently suing the guys who taught her the "trade":

http://www.backstromandheinrichs.com/Case-Updates.shtml

The beauty of that case is that Pam and Joel "Jim" Murphey effectively identified a bunch of other employees - which made it much easier for their victims to track them down!

CMAG/CM Association Group et al is currently registered with the California Secretary of state as CM Association at 1800 E GARRY AVE #114 Santa Ana CA (although they also give 108 Business Center Dr, Corona, CA as an address).  

Gary Boyce, their registered agent, is an employees/debt collector.  Until recently you could see Gary's and other employees' pictures on Pam's facebook page but she apparently got nervous and completely deleted her facebook account (no worries Pam....we made copies of everything before you took it down).

Interestingly in that same building is attorney Luis Vasquez who was associated in the past with the infamous debt collection racket known as Shekinah:

http://www.budhibbs.com/collectorpages/capital_recovery_services.htm

Attorney Vasquez has recently been disciplined by the California Bar Association:

http://members.calbar.ca.gov/fal/Member/Detail/162798

Vasquez also seems to be associated with another notorious debt collection James Novella:

http://www.corporationwiki.com/California/Tustin/james-novella/66466385.aspx

File a complaint with the FTC and be sure to include all the contact info/aliases you have from your dealings with them:

https://www.ftccomplaintassistant.gov/

The Commission does take these Corona area scams seriously:

http://www.ftc.gov/opa/2011/10/rincon.shtm