Beyond these comments, I'm not going to waste any more time on someone who's not willing/able to be rational or logical.
If the Potion was actively breeding females while in Xavier's collection, then it's not even remotely misrepresenting it to call it a "breeder". Pretty basic stuff, there.
It's not THAT Brandon/Tom chose to breed it, it's WHEN, that is the crux of this issue. If they had practiced quarantine procedures, or even provided a reasonable acclimation period, the situation would likely be very different at this point. If they had followed sensible protocols, and the Potion still died, they might have had a leg to stand on, in demanding reimbursement.
However, they did not do this. As it stands, they chose a course of action that shows a blatant disregard for the Potion's well-being, as well as for their entire collection. If you're willing to take such reckless risks, you better be willing to accept responsibility for the consequences, when they backfire in your face.