If you look through the forum, you'll see lots of folks have lots of problems with this awning. We have one also. Like you, sometimes I wish we just had a manual one. However, when it works it is nice to push a button and have the awning deploy. On ours, the controller board needed to be replaced. It is now working better.
Suggest you call Zip Dee and talk to technical support there. You'll probably talk to a guy named Randy. They might be able to suggest something to try. Worth a call.
If that doesn't get you anywhere find a better dealer to take it to. I agree with LAWBC that the dealership you went to is just giving you excuses since they don't know how to fix it. You can use the Airstream corporate website to locate all the candidate dealers near you and then see if you can find any opinions of the service departments for those dealers on this forum, particularly when it comes to repair of Zip Dee awnings. You may have to travel a ways. We drove over 150 miles to get ours fixed. Zip Dee tech support can also help you with identifying a dealer to go to. They know which dealers know their products best.
2019 Globetrotter 27 FB
2018 Chevy Silverado 2500 4WD LT