Convergent Outsourcing Inc. Galaxy Asset Purchasing, LLC Attempting to collect on a false debt Renton Washington

This may not be a scam.  There are a ton of scammers out there trying to collect on a "debt" that doesn't exist.  Your post is a little different because of the amount and the name of the collections agency.

Check out your own public records to see if there is a judgment against you. Sounds like it from the amount. Did you ever return a car back to the dealership without paying the balance? 

Check to see if the collections agency is a legitimate agency.

Also, check to see if the debt is a legitimate debt. You can request for the creditor to validate the debt. Look up the proper method.

One last thing is to make sure that if the debt is legitimate and the collector is legitimate - make sure the collector has the authority to collect on this specific debt. 

If they are all legitimate and they have the authority to collect on the debt then seriously consider working with them to pay it off. JMO. Good luck.