It has been reported that this is Omega Mediation Services, a criminal enterprise pretending to be a legitimate debt collector.  Following is what you need to do and to know:

You need to send them a certified, return receipt debt validation, cease and desist calling, or "not me" letter.  You also need to report them to the proper agencies to which I have provided links to.  Then you need to go out and get a consumer lawyer to sue them on a contingency basis (no money out of your pocket) and let them pay you for the harassment.  If everyone did these three things, these crooks would be bankrupt and we would all be the richer for it.

OMEGA MEDIATION SERVICES AKA REASONABLE SOLUTIONS, LLC.
Posted in:  http://800notes.com/Phone.aspx/1-855-737-4045
http://800notes.com/Phone.aspx/1-732-231-8098
http://800notes.com/Phone.aspx/1-888-502-3107
http://800notes.com/Phone.aspx/1-412-697-4124
Web site lists them in South Carolina:  http://www.omegamediations.org/contact.html
That address comes back to a different debt collector:  http://yourreasonablesolution.com/contact/
Using the catch phrase “pre litigation”.
BBB gives them no rating and no complaints, but the file was only opened January 28, 2016:  http://www.bbb.org/charlotte/business-reviews ... -hill-sc-462331
BBB gives Reasonable Solutions no rating with 1 complaint:  http://www.bbb.org/charlotte/business-reviews ... -hill-sc-415505

No corporate registration found for Omega, so they are not legally allowed to do business.
South Carolina Dept. of State info on Reasonable Solutions, note they haven’t been in business a whole year yet:
REASONABLE SOLUTIONS, LLC
Note:This online database was last updated on 2/2/2016 3:05:37 AM.
See our Disclaimer.
DOMESTIC / FOREIGN:    Domestic
STATUS:    Good Standing
STATE OF INCORPORATION
/ ORGANIZATION:    SOUTH CAROLINA
Profit
REGISTERED AGENT INFORMATION
REGISTERED AGENT NAME:    HARRIET JACKSON
ADDRESS:    331 E MAIN ST
CITY:    ROCK HILL
STATE:    SC
ZIP:    29730
SECOND ADDRESS:

FILE DATE:    02/13/2015
EFFECTIVE DATE:    02/13/2015
DISSOLVED DATE:    / /
Corporation History Records
CODE    FILE DATE    COMMENT    Document
Domestic LLC    02/13/2015    SCBOS Filing: AT WILL

Looks like they were sued already:
http://www.law360.com/cases/5661f7e31da9fb3076000001

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