caller i d said washington.

Got a call from this number also.  I have no idea who it is.

this is washignton mutual, wich is a credit card company and you have a past due bill

I have a wamu account, but my account isn't past due, but went over the limit this month by just a few dollars, so they started calling.  they continue to call me--sometimes they leave messages and sometimes they don't.

It is Washington Mutual trying to sell you more services.  Some other numbers you may see are:
775-332-0228
480-296-0235
I just told them to remove me from their lists.  If you call back and keep hitting "0" you will eventually reach a real person.  I am a new checking account holder and they are using my contract info to sell me other services.  
I have received almost 20 calls since Saturday.  Good luck!