Not accommodating enough

Had a winner yesterday at my part time job. I work pt for a regional convenience store in NY known for its dairy products. So, yesterday was a mess, came in and had to count the tills, lot to tickets, salt the parking lot, etc. In the middle of this, had a customer ask for a diet version of the store brand cola. We haven't had it in nearly 2 years, pretty sure the company just stopped making it, but she had a bit of an attitude, so I figured I'd humor her by checking in the back anyway. Told her we didn't have it, then got treated to a lecture on how she's diabetic, which makes her disabled in NY, and by failing to have the store brand in a diet cola, we were violating her rights by not accommodating her. I told her we had Diet Coke, Diet Pepsi, Coke Zero, and Pepsi Zero, but she doubled down and said she was going to report us to the state attorney General for violating the law by not giving her an accommodation. My coworker chimed in and agreed with her and said she didn't understand why we were the only store out of nearly 400 that didn't have the diet cola. I looked it up and we literally cannot get it (either they stopped making it or they didn't authorize it for our shop). I told the customer to come back later and deal with the manager