u/Funny_Ad4078

I've just gotten back into bowling and bought a ball. Proshop owner did the customization and I was raring to go. However, I generally have some hook to my shots and there are times where my thumb gets stuck to the ball. Tried going back to proshop to drill the thumb hole bigger but was advised against it and instead owner told me that I may be used to death gripping the house ball, hence getting stuck. Any advice on how to properly release the ball? Thanks in advance!