She may give you eggs yet, but if she does not lay, then you could RETURN THE SNAKE FOR A REFUND, according to the guarentee you quoted. The snake must have egg(s) in order to qualify as gravid, so if she does not at least lay one slug.. then you got a non-gravid, which means you could get your money back BY RETURNING THE SNAKE.
I'm not sure why you feel you would be entitled to keep the snake, get your money back, and get some of his hatchlings?