If the property is your owner-occupied primary residence, the subcontractors(subs) are required to provide you an information notice called "Notice to Owner" found here http://www.lni.wa.gov/Forms/pdf/625054af.pdf
Considering that your project is a flip(purchased with an intent to resell for profit), the subs may not be required to provide you the notice mentioned above but the general contractor must provide you a different notice called "Notice to Customer" found here http://www.lni.wa.gov/Forms/pdf/F625-030-000.pdf
Assuming you paid your general contractor in full, you may want to try the following options:
1. Contact your general contractor in writing(certified mail with RR) demanding that he pay the subs and confirm that the subs removed the liens within 7 days or you would file a complaint against the general's license with the Washington Labor and Industries Contractor Licensing Dept.
2. If option 1 fails, you may pay the subs by yourself with a written agreement between you and the subs stipulating that the lien will be released immediately upon payment; then file a complaint against the general contractor. To file a claim contact the L&I via this link
http://www.lni.wa.gov/Main/ContactInfo/TradesLicen...
Note that after filing the complaint with the L&I, you will still need to suit the general contractor in court and get a judgement in order to get paid from his license bond.
3. If you don't wish to contact the general contractor as suggested in option 1, then you will need to pay the subs to remove the lien, then file a complaint with L & I then court.
In the future, make sure to post a bold notice at the job site requiring all subcontractors, material suppliers and employees(whether employee of subs or general) to provide you with their names and contact information before starting work on your job site. When it's time to pay, request lien waivers from the general contractor for all subs, material suppliers and employees.
Hope this helps