Breastfeeding when Shopping

So today I was shopping at Ross my 6 month old daughter was hungry So I when to the fitting room so I can feed her their. I always do that at every store and there is no problem with it. But today was different. I asked the lady if I could go in to feed my baby and she was like no we need the stalls for people that want to try something on. I said ok and walked away trying not to snap on her. There were like 15 fittings rooms and she acted like they all were going to be use. I was so mad 😠😡. What would you do In my case ??