Did you discuss with your T what his policy is on emails? Some Ts don't allow them, use them only for scheduling purposes, or allow emails but don't respond to them, or allow them up to a point-- but change course if they perceive the client is overusing email. It may be that he has boundaries around email use that he feels you violated. Or maybe his policy is not to respond. Do you know his boundaries? Maybe he does care but is following a specific policy. Maybe you could ask him about this instead of just quitting? He might have a reason.