Firstcry.com — Babyhug diaper size fit and leakage issue

I had purchased Babyhug diapers S Size, even though my baby weights only 6 KG and this diaper should fit to 4-8 kg the diaper is not fitting him in waist and the tape comes off, my baby's clothes got wet till his chest just after using two diapers .

I asked for refund then they told me to share one video in which they were expecting to see the diaper leakage just after pouring 100ml water, I shared the video and they rejected my request saying that diaper is not leaking in the video .My concern was that bsbyhug should work on the quality of tape and increasing the waist size of the diaper like pampers so that no customer will face this issue.