If I were in your shoes, I'd contact them immediately & tell them exactly what you just said above; they don't want their snakes going to ppl that don't have prepared
caging ready for them, not if they're good enough breeders to be worth buying from.And they have some prep to make also, & don't want to ship a snake that
has just fed, for example.
Breeders are individuals of course...but I think most will appreciate the head's up, & may ask for a deposit (partial payment).