Very disappointed and distraught, you've lost a customer

On Friday the 11th of April I asked my sister to go buy a rainbow number 7 helium ballon at Cardies inside Mall @ Reds Centurion for my daughter's birthday which was the following day. She got the ballon just after 3pm in the afternoon, we did a bit of shopping and went home. We got home, neatly tied up the ballon and within an hour or so it just burst on it's own.

I woke up the morning of the party and went back to the store to request a replacement. I was told it's against their policy and that they cannot assist. This experience almost ruined my daughter's party as you can imagine how devastating this was for her and me. I was given a number to call which is still on voicemail. My thing is, if maybe my daughter was playing with the balloon I would fully own up to her possibly causing the burst. But in this instance nothing happened, the balloon burst a few hours after being bought before we could even make it to my daughter's party. I am truly distraught, atleast sell us good quality products if you are going to be instilling such policies, not this cheap quality that we were sold.