2004 Pontiac Montana Question: AutoSliding door won't close properly

Some one Someone hit my van in parking lot and now auto door makes like it going to shut but can't line up properly at the very end of the closing. I've cleaned the contacts, checked the rubber strip but that's not it. It seems like when they scraped me in the lot, it jiggled the door alignment off. Ve got it in a repair place and they've had it 3 days and I don't think they know what's wrong! I've heard nightmares stories about this subject. Any solution or help would be greatly appreciated. Using iPhone sorry for typos, etc.