There could be a number of reasons for that. If it is a baby rabbit, it will not develop litter habits until it's a bit older. Regardless of age, rabbits put in a new environment will pee and poo everywhere for the first few weeks until they settle in and pick their "toilet spot". Rabbits who are not desexed will also feel the hormonal urge to spray-mark everywhere.
Wood chip pellets, also known as horse stall pellets, are VERY cheap and an excellent litter material, I and many members on here use it.