I had some similar frustrations with my garage door, although not as bad.

My door would go down and then reverse and go back up.

I lubed and greased everything really well. No change.

Checked the safety sensors, cleaned thoroughly - no change.

Adjusted the force setting on the motor. No change. Hm...

Adjusted the safety sensor just a little bit... Bingo! Garage door works fine.

I was amazed that something that looked perfectly straight caused such grief.

Sorry I have no real help to offer, just a little sympathy.