Installing bmw door panels

Quite a predicament. I think it'll be hard to help without seeing exactly what type of clips they put on your car. If you don't want to go back to the same guys (and I understand you completely), I think it would be best to look up another shop that knows how to deal with BMW's. I don't know if the first shop you went to specialized in BMW's but when dealing with these little issues it often helps going to someone who knows exactly what they're doing.

Anyhow, it's worth finding a shop you trust for the future, cause you are bound to have, as the car gets older, other issues that will need attention 

I know you feel uncomfortable going back but you need to do so. you paid for a service that was not done right and they need to rectify it. and you should make it clear that you will not pay for the same job twice. you as a customer have rights and they need to know this. good luck.