Sounds like a keeper to me. Is it a covered litter box? Many cats don't like boxes with covers, and many don't like "scented" litter. So, if he's not using the box still, he might have a urinary tract infection.
One of our cats is litter trained, but he prefers to go outside & will cry and cry to go out. If we don't let him out when he cries like that, he will purposely pee somewhere inappropriate, like the bed, sofa, or dining room table. He has us trained to put him out at like 5am when he starts crying at us.