Hi, I had the same issue on my Dell XPS 15 laptop. Even though we have different models I think my fix might work for you as well. When I opened up the back of my laptop the port to which I plug in my charger on the inside would slide back and wasn't properly fixed down. To fix this I simply stuck a piece of plastic behind it so it wouldn't slide and taped it down. I wouldn't spend so much money on such an easy fix seeing as this is just poor hardware design on Dell's part. Hope this works for you :)