collectcorp and now Viking Collection service

No, two collections can't collect the same account. It is possible one has bought the debt and the other is collection for the first...they do this. Send the new company a DV letter, reiterate that you want full and complete validation, you want to know who currently owns the debt, the last statement showing then final amount due and a signed contract/agreement. You can also mention that anything less would not hold up in a court of law. (Some CA's like to be cute and say they don't have to provide contracts and such...but in a court of law they do.)

There is always the possibility you will get sued, especially with that amount. But it is your right to demand validation otherwise how do you know you are paying the right people the right amount? It seems that those who can't provide validation won't be able to produce it in court either.

Viking do BofA third party and the poster did say "assign"...so sounds like account has been pulled from one agency and assigned to another.