Petco Dog Training

I purchased a couple of emerald corys to add to my fish tank yesterday; however, 1 of them unfortunately didn't make it through the night. When I went to replace this fish I was assisted by Jacob, who was a great help, but left about as soon as I received the replacement. I walked about 20 feet before I took a look at the fish, to which I noticed it was swimming frantically and occasionally upside down. After the short observation, it was very clear the fish probably wouldn't make it in the tank, much less the 5-minute trip home. So, I returned to the fish tanks and waited for an associate to be free as Jacob had already returned to the back. Bailey approached and asked if I needed help and I explained the situation. Rightfully, she asked me if I dropped the fish and I said I had not and hadn't moved very far after receiving the replacement. She immediately snapped back with, "well this only happens if the fish was dropped." If I dropped the fish I would eat the cost because that's on me, but I didn't and the snappy comment was uncalled for. She took it upon herself to walk the fish up to the register, fine by me, but her expression showed her annoyance to the point another associate commented. She checked me out and reminded me that a physical receipt was needed in the future. I declined my receipt from the original purchase because I thought I received it through email. I wanted clarification on whether Petco sent e-receipts and started to ask but she interrupted me halfway through to say "We are not responsible for keeping track of your receipts." Of course, the store isn't responsible and she would have known I wasn't asking that if she waited for me to finish my question instead of jumping to conclusions. I understand the frustration of having to deal with unreasonable customers, especially working in the pet industry where I'm sure many customers probably walk in with little knowledge of the care needed. But, she immediately took me as someone with no knowledge and showed her frustration and annoyance with me every step of the way until I walked out the door.