Litter box and spraying can cause frustration to every cat owner. You will find help in understanding what causes the behavior to begin with. It’s could be caused by a urinary tract infection, a territorial response, new home, new baby, new litter box, new pet, new litter, not enough litter, the wrong box, location of the box, not enough boxes, you name it! Please be aware and understand that punishment is never the answer. It might make the situation even worse.
The first response to your cat not using the litter box should be a trip to the vet to eliminate any physical causes such as a urinary tract infection (the most common cause). Spraying is marking the territory. If your cat has not been neutered, you should consider it.