DeeDee

Hello, We had a new fiberglass pool put in the ground in October/November time frame. The pool was filled about two thirds of the way up. Now after rain, snow melting, etc. the water is up to the water line tile line. We can see the pool is not level. The ends are level looking to each other however the sides of the pool where the curves are on both sides are about three to four inches higher than the ends. What would cause that?