Sorry to read this.
Please do not let it deter you from online ordering. The overwhelming majority of these transactions go very well.
There is a ton of conjecture here as to what exactly could have caused this, but really it kinda does not matter. It is the end result of poor customer service and a sick (now deceased animal) that needs the more immediate attention.
I agree that if you just want a refund, that is what you should get. I assume there is at least a partial refund coming with the less expensive snake?
Good on you ColdBloodedAddict for stepping up to the plate!