As nigel says, don't give up with the claim, as travel companies will attempt to get away offering the least unless they are pushed...
I do ponder though whether your insulin did go off or whether they main problem was how your body/diabetes reacted to the change in climate...
A couple of tips for emergency back up of keeping insulin cool..
Buy a Filo pouch, this is water activated and keeps going, when the crystal start to try out, just dunk in water to reactivate...
Air tight container that your cartridges will fit into, either as whole pack or the individual cartridge blister pack will fit into, you then dunk this into a bowl of water, may have to weigh it down a bit to prevent it floating, keep replacing the water to maintain it cool... This I know from experience is very effective way of keeping insulin cool.. And remember to keep it all out of direct sunlight...
But if you are in different climate that you aren't used to, and you have replaced your supplies for new and still experiencing problems with blood glucose, then it's more likely that it wasn't the insulin going off but your reaction to the change in climate that has effected your control..