I think you've an FDCPA violation to go with the fact that they're not operating legally in Wa.
http://www.ftc.gov/os/statutes/fdcpa/fdcpact.htm
Here's a snippet from 807:
(2) The false representation of --
(A) the character, amount, or legal status of any debt; or
And here from 808:
§ 808. Unfair practices [15 USC 1692f]
A debt collector may not use unfair or unconscionable means to collect or attempt to collect any debt. Without limiting the general application of the foregoing, the following conduct is a violation of this section:
(1) The collection of any amount (including any interest, fee, charge, or expense incidental to the principal obligation) unless such amount is expressly authorized by the agreement creating the debt or permitted by law.
I really think between the liscensing/bonding issue and this attempt to collect more than the creditor says is due,you have grounds for a nice lawsuit. Have you looked for a lawyer?