Bottle lids coming off feeding bottles

I was using from my 1st born and the issue I'm having right now is that the 260ml bottles I bought for my now 9 months old have loose lids. Lids keep coming off because they are no longer and I do not understand what the cause might be. I wrote to Philips Avent via Facebook but did not receive any response. I'm really now disappointed because I love the brand but this is risky for my baby to sometimes find his feeding bottle with no lid. Please do something about this issue Philips Avent