I took our cat to the vet about a month ago to have her spayed and wormed. I did not realize until today, that they had given her a worming tablet that was for a dog. They sent me a bill for extra monies and after looking at my bill which was paid in full, I saw that she was given Iverhart Max, which is prescribed for a dog. What should I do? I'm sure not paying them extra for giving the wrong medicine.