Review on Bansusu Primary Rolling Backpack - Enhanced Satchels for Efficient Backpacking by April Goracke

My mother (his grandma) bought this bag for my 12 year old son as a birthday present. He is in the 7th grade and has to carry a lot of heavy books. We were all so excited when we found him. My son loves space and he really liked the space theme and all its subjects. However, after a week my son stopped using the bikes. I asked why. He said he had to climb narrow, crowded stairs to get to class. So he had to put his back on his back. At the same time, it continued to separate and became a security threat. I didn't want to contact the seller but I changed my mind. If you can solve this problem then 5 stars. I know why it's coming off, but can you improve the design? Many Thanks.