as mentioned above--find a new shop, even if you have to travel to do it.
for many years, held high averages in THS, always lofted the ball a bit. decided to try the sport game, found out how flawed my fundamentals were.
best thing, by far, that helped me was a proper fit
i hadn't ever taped a thumb-hole til 4 or 5 years ago
now, with proper tape, i have learned to relax my grip and it has helped tremendously
your fit is everything, only a seasoned professional can help you