How to fix songs still waiting in iTunes Match?
I would export a copy of those songs to a folder in /Users/Shared and then turn off iTunes Match. Then:


Make a new user on your Mac
Log out of your existing user
Log into this brand-new user and fire up iTunes 


It should have no music whatsoever and not be linked to your Apple ID. Now go ahead and sign into iTunes match and see what the cloud really thinks your music library looks like. Drag one and only one song from the users/shared folder into this library and leave iTunes running for a while to see what iTunes match makes of it. 

At that point you have a very isolated and potentially reproducible issue that you could reach out to Apple support in case the problem is on the server side and nothing that you were doing.