Tiguans stay far away from sunroof

I bought a Tiguan 2017 2.0 tsi highline and whenever it rains I get a bad smell from the vehicle only to find out that it is coming from the sunroof now I took the vehicle in on several occasions and they said it is sorted.It has not rained in a few months so I still continue driving the vehicle,I then went to Facebook to join a group called Tiguan *****s but it seems that they have the similar issues I’m dealing with.The service at vw Rustenburg was so poor that I had to over inspect the vehicle every time I got it back as you could visibly see the poor workmanship of the dealership.I am very disappointed as I have been driving only vw since 2008 and stayed loyal to the brand but I now need to reconsider as I’m stuck with this shining turd.