Rhonda
Contacting the original creditor is the smartest move. In the meantime, keep tabs on any complaints you make against Ted Crosby. He's currently hidding, apparently, and is already in trouble with his previous company Ellis Crosby & Associates. Paying "Interstate Collections", would not only mean that you'd have to pay again, but they'd also keep the money. They're having you send it via Western Union, which means it would be almost impossible to prove who you really paid.
And always remember to remain strong when speaking to them on the phone. You're the one who is in control.
Regards-
Mike