Tommee Tippee hiding behind policies.

Half of our tommee tippee bottles markings came off after a few months. My question is why is some of them still printed and some worn off? Friends of ours have a cheaper brand and at the same age all still have their printing on. Jenna rep**** with a bunch of excuses and small print excuses. I will definitely not use them again. They know babies are on bottles for about 2 to 3 years but only cover the first 6 months. Do they expect us to use a measuring cup or buy new bottles every six months?