Do you think I owe a refund?

For your consideration:

Let’s say I sold you multiple frogs that had been housed together by me, the seller. One of them died from what appeared to be an infection. There were visible lesions on the skin. This frog died within the 7 day period I gave for a refund. Following that period, several of the other frogs died, apparently from the same infection as they had the same lesions and symptoms.

Now, would I owe you a refund for only the first frog that died, since it was within the 7 day period? Or, would I also owe you a refund for the other frogs that died. And what of the remaining frogs that may also be sick and carrying this disease? Should I be expected to take them back and refund you or are they yours now?

Discuss :D

(disclaimer: this is purely hypothetical)