Instruct: Classify Amazon reviews into positive or negative sentiment
Query: not satisfied

Not satisfied with this product at all. I purchased it since the bottles that come with the pump are polycarbonate. These bottles do not seal properly. If you try to shake the bottle, it leaks everywhere. Even during pumping if you hold the bottle at an angle at all, it sometimes leaks. There are not enough rings at the opening for the bottles to close completely. The least the company could do is make good substitutes for their polycarbonate bottles - since it seems to me they quietly market the fact that these bottles can replace polycarbonate bottles as a "safe" alternative.