I have brought the ruckus on a few places and had good results. I needed sun block one day, and dropped into a Walmart to grab some. The dept. that sold the sun block was right next to the pet supplies, so I took a gander at their fish. They had a 5g or so tank with about 6 ck's in it. It was bare bottom, no hiding places, and they were throwing flake food in there, which the ck's had no idea what to do with. The fish were starved, stressed, and in bad shape. I was on fire over it. I told the dept. employee, I told a couple of managers, I did all I could, but no one cared. So, I got mad. I called the general manager and the regional manager. I explained the situation, explained animal cruelty to them, etc... and told them that I absolutely would not drop the issue. They no longer sell ck's at that store.
I also came uncorked on a local Petco for torturing some poor little leopard geckos. It was an ugly mess. I need to see if I still have pics of the starved little guys. The manager ended up giving me 2 to see if I could save them, but they were too far gone. I did all I could. They were thinner than anoles with I took them. Conditions have improved greatly at that store as a result.
You have to word things well, and not drop the issue. You sometimes have to be a voice. It sounds cliche, but seriously, we have to be voices for things that have none. It isn't enough to just not support a business.