Hello Emilia, thank you for bringing this to our attention. We're so sorry to hear this. Pumping takes so much work, and we share your frustration in seeing that work go to waste. For the best performance from our Breastmilk Storage Bags, we recommend filling with 6 ounces or less, removing the excess air before sealing, and laying flat to freeze on a paper towel. Having said that, the performance you describe is not typical, so we would like to learn more. Please contact us directly at wecare@lansinoh.com and a member of our Consumer Affairs team will reach out right away. We look forward to hearing from you and making things right.