Did they have records of the baby eating while in their care ?
As terrible as it sounds, some unscrupulous people will sell a baby that has not eaten or has only eaten once, and when someone inexperienced gets that baby, things like this happen.
I made that mistake once, with a person I thought was a reputable breeder. Turns out he routinely sells babies that have only eaten once and doesn't see anything wrong with it. If you can't get the baby he sold you to eat, then you are doing something wrong. At least, that's the story he gave me when I told him a baby I had recently bought would not eat. After 3 months of trying, and he finally admitting he didn't know why the snake would not eat, we found someone with experience tube feeding who was willing to take her. To this day that snake does not eat like it should.
I learned my lesson, reputable or not, I'm not buying any snake from anybody that hasn't eaten at least three times in a row.
Gale