Please accept my condolences. It's very hard to impress on people the real importance of quarantine let alone housing ball pythons in the same enclosure. Quarantine is your first line of defense to view any abnormalities, illnesses, or irregularities in new acquisitions. It also is a protection for you, your animal, and existing collection. Once that defense is breeched you are at risk. You already know that the big box stores are notorious for poor healthy practices. Chalk it up to a unfortunate experience sadly and learn from it. Always buy from reputable breeders who are committed to producing healthy, quality animals. They are right here on this forum. Again, sorry for your loss.