Food poisoning - it couldn't possibly have been Jetstar

I ordered a toasted ham and cheese sandwich on the flight. The toastie had to be heated up and was sad and soggy when I received it. It was the only thing I had eaten that morning. I got off at Cairns to catch another flight. Stomach cramps began immediately in Cairns. I drank water only after that. Cramps continued during the next flight. Could not eat. I had to lay down when arrived at destination 3 hours later I was so ill. At 9pm that evening I was projectile vomiting. I had several episodes during the night and the early morning. I was suffering. I could feel myself improving during the next day so I did not consult a doctor, as I suspected it was food poisoning from the toastie.
I contacted Jetstar and they said they would respond within 15 days which they did. They denied it was them and it must have been something else I ate. Their procedures and 'exacting standards' couldn't possibly have caused the food poisoning. After several email exchanges and denials by Jetstar I asked them to answer one simple question:

"...Am I to understand that you saying it is impossible for your food to be contaminated? Please respond to this specific question..."

They didn't respond.