How cold was it in your house?
Veileds in the wild have been know to survive freezing temperatures. Not that this is something you really want to do to a captive animal but I think you should look again at what your husbandry was with the veiled. The veileds that come from the mountains have very similar enviroments to a Jacksons. If there was a flaw in your husbandry it will need to be corrected or more thought out Jackson chameleons are way more sensetive to mismanagement then a veiled would be.