I presume that you did not not delete your iTunes library from within iTunes. Can you recover from trash? Also why did you manually delete your time machine backup? Time machine manages your hard drive space and removes older backups when more space is required.
If you have iTunes Match, open iTunes and turn on match.
If you see the tracks listed and you see the " ! ", delete all tracks but don't delete from cloud. Highlight tracks and download. If you see the tracks with download icon, highlight tracks and download.
Thanks Jim it seems to be working. Nearly all my tracks have "!". A few now have the cloud download icon and they are very slow to download from the cloud. I have a slow internet connection so may be selective on which music I want downloaded from the 4900 tracks I had. My Time Machine for some reason was not working properly so I re-formated my external drive, and now it is working. Many thanks, Jason
I can't say how grateful I am to see this. iTunes support was completely worthless while I tried to get an answer to this very question. I found that when I double-clicked an individual track, it gave me an option to search, and when I selected "Cancel," the song appeared with a download cloud. EVERY song/track in my library not purchased from Apple has the "!", and I was going nuts trying to get everything recovered. The exchange was one of the MOST FRUSTRATING experiences I've ever had with Apple, and I'm seriously disappointed in the whole thing.
Anyway, thank you so much for answering this; it's working brilliantly for me.