iCloud music library won't sync

I've had this issue off and on for about 3 years now but lately it has been really bad. I used to think it was a problem with my wifi but now I'm convinced it's apples crappy software. When I try and sync a song into my iCloud music it gets stuck on accessing music library then gives an error saying "iCloud library can't be updated, an unknown error occurred" followed by a random number. when the started happening today that # was 50 but in the past it has been other #s such as 19 or 42. I have contacted apple support about this and after explaining what the problem was the service "advisor" just started completely ignoring me. that was about 3 weeks ago and the problem still isn't fixed so since apple won't help me I am turning here. does anyone know what I can do to get my music uploaded into iCloud. I've tried signing out of my account and signing back in, restarting computer, restarting iTunes, repairing iCloud library, syncing the songs one at a time as opposed to updating the whole library at once and nothing has worked.