Mother can't help her kid in the fitting room 🙉

I am still up set about H&M so called Policy regarding fitting rooms. My daughter and I were at high street mall and decided to buy a dress from H&M. We bought a dress and about to leave the store when my daughter saw a top and decided to try on so we went back to the fitting rooms. The top was quite challenging and had a choker like collar which was quite hard to put on so she called me to come in the cubicle and help her while I was struggling with the buttons and trying to figure out how to undone, the fitting room attendant yelled at me from the other side of the curtain to get out, I asked I am helping my daughter so let me finish the job, she yelled again you are not supposed to be in the fitting room. I explained but she refused to listen. So I asked to all the manager ( another teenager) who said yes, this is true and and for loss and prevention reason you are not allowed to be in a fitting room with your daughter and let me remind you that my daughter was trying only ONE SHIRT. Long story short, I returned the dress too( didn't by the damn top either) and left the store. I am so disappointed and never going back to any H&M store. It was your loss H&M.