Instruct: Classify the given review as either positive or negative.
Query: Lost a loyal customer- changed formula without notifying customers

My dogs had been eating canidae since they stopped eating their puppy food. They did great on it until yesterday we bought a new bag and they became violently ill after only eating one bowl. This was the only variant in their diet.I returned the bag back to the pet store and found out they had changed their formula because ingredients had become more expensive. They did not even notify consumers!My dogs have very sensitive stomachs. What they may consider a simple change made them very sick. This is a complete disregard for the dogs they supposedly care for. I understand they need to make money but notify the consumer so they can make an educated decision or buy the old formula at a higher price.