There are two things that need to be said here:
  1. You did not "surrender" your animal to PetSmart - you brought it into the store, you gave it to the store to keep while under the care of their veterinarian, and you were likely given a refund. The last part (or the entire part) of that interaction would have happened at the cash register. It would have been nearly impossible for you to not know what was going on during the return process.
  2. PetSmart has always reserved the right to refuse the sale of any pet (except those they specifically carry as feeder animals). They are well within their right, and the law, to do so.


Now, if you were blatantly lied to during the process, that is another matter entirely. That is something anyone would be upset about, and rightfully so. I know it's difficult to do so, but if you take emotion out of it, what really happened at the store that day?

Best of luck to you! You have really been through a LOT so far, and I genuinely hope things get better soon.