found a receipt showing that 13 years ago we were overcharged $500 for a veterinarian visit. is that too long to try to get our money back that they o

We purchased a dog from the SPCA 13 years ago. Before being able to take the dog home they had to be taken by the SPCA to a vet to be spayed and have all the shots. The day I went to pick the dog up they told me it was three hundred and some dollars so my husband said Put it on the credit card and we did pick the dog up all the information in a little folder we have well she passed away a couple weeks ago so we happen to be going through our information and we noticed that the printout of cost the total came to the three hundred and some dollars but the credit card receipt that they charged was for 800 and some dollars they overcharged US $500 and we never even noticed it until the poor dog died what is the chance of us getting that $500 back?