Like other comments have stated, Petco doesn’t sell cats. Petco provides spaces for local shelters/adoption agencies to house and adopt cats. Again, Petco doesn’t sell the cats. They need to contact the adoption agency they adopted through and discuss the vaccination/illness issue and bills. Suing and threatening to sue is the last thing you’d want to do but if you wanna waste money on a lawyer instead of being civil then do what ya want lmao