This company is called Southwest Credit Solutions yet they're website shows them as SWC Group (http://www.swcgroup.com). They're violating the FDCPA (Fair Debt Credit Protection Act) by using a Philadelphia area code when they're actually based at the following address:
Maintain a call log that has the date, time and number they used to call you as a written record of each violation they commit. Also, send them a "Cease and Desist" letter (http://www.shaklaw.com/debt-collector-cease-and-desist-letter) via registered mail with return receipt. Once it's signed for and they continue to harass you, you can then file a lawsuit against them. I've done this against two other scam companies and won with ease in 2010.