You might want to figure out why the rabbit died before you immediately start to blame the woman selling the rabbits. Rabbits do die unexpectedly from many things, including stress.
If there was a vender selling rabbits(or indeed, any animal) that were unhealthy, then I hope you get your money back!
We found out that the rabbit she had sold us as a pet was only 3 weeks old. So yeah, I'd blame her.