TPK PRIVATE TUTORING NOT FULL FILLING

Good day I signed a contract with TPK PRIVATE TUTORING to assist my grade 12 son, I paid 50% of the amount charged and the tutor came for 1 lesson on Saturday and he's supposed to come tomorrow Wednesday. I called the TPK to confirm for tomorrow the person is not taking my calls nor whatsap. I called the person (tutor) and he told he can't continue because the TPK did not pay him and his not taking his calls either.