Non Spill bottles are terrible

I probably have 9 tommee tippee non spill bottles if not more every second month i need to buy 2 new ones. I don't know why they are leaking. Those bottles are so expensive, they are not supposed to only last for two months. I bought 2 new bottles 3 days ago the one is perfectly fine but the other ones rubber keeps popping out so when my daughter drinks her juice its all just flowing out her bottle. This is really ridicules. i can not keep on buying bottles if they don't leak they are faulty. Tommee Tippee i hope i hear from you soon. This is no the first time i had problems with tommee tippee , why are your prices so high if the quality is so weak.