Viking Client Services, Inc. Debt Collection Complaint

Viking Client Services, Inc. Debt collection department,

I do not know Cont'd attempts collect debt not owed Debt is not mine District of Columbia

My cell phone is registered on the do not call list. I received a call from someone who asked for a relative. I told him he was calling a cell phone and it was not the number of the relative. He told me my number was listed as an alternate contact number, which it is not. He asked if I could get in contact with the relative and I told him I have no communication with the relative and hung up. He did not identify himself or his company name. However, I looked up the phone number on the Internet to find out what the call may have been about.