Poor quality product

I purchased a packet of Nik Naks for my daughter to take to school for her birthday celebration. The pack I bought carries multiple 20g packets! My poor child came back in a state after she was made fun off by her peers for bringing half eaten chips. I could literally count the amount of chips in a sealed packet. In comparison to other packets we had about 5 which were unacceptably empty. I need to understand why this is, if I were looking to resell these, what then?