Hi herf,
Since the heat pack was cold when you got the plant it is entirely possible that it was defective and actually cooked the plant. That is why some vendors refuse to use/sell heat packs. They can be a blessing or a killer.
It's still no reason for the seller to be rude, something could have been worked out. Chock it up to experience and move on.
I know it hurt the budget but some times there just isn't anything you can do.
Regards,
Al
P.S.
I have a seedling I'll give you if you would pay postage. With good care you might get a bloom this summer/fall..........however it is small....something to watch grow and it will be something no one else has (seed cross so they are all a bit different) P.M. me if you are interested.