I feel your pain..
I did this to my Rx300 years ago only a few days after I got it-- only it didn't get stuck (ouch!!). It hit the metal bar which hangs low when the garage door is open.
Anyway, when I got my rx400h, I was perfectly aware of the garage door thing. Here I some things I discovered.
1. I can open the backdoor if the garage door is closed. The metal bar which hangs low when the garage door is open isn't there for it to hit. THe car door opens almost straight up so it won't hit the closed garage door. I have just enough room behind my car to remove groceries, etc.
2. If I have to have the garage door open-- I open it manually (not with the auto button!) and let it come to gently rest against the bar and then use a towel to go between the garage door and the back door at the point of contact.
Now, of course, this is my garage/garage door-- it may not work for yours.
When this happened to my 300, I had them buff out the scratches and it made them much less prominent without having to get an expensive repair (hope your car isn't black!!)
Sorry, dude, but this isn't your dealers fault. But I do feel your frustration, been there-- done that!!