(and) that's that
That is final; the issue is settled or completed. You are going to your sister's recital and that's that! No more complaining. That's that! I just send the proofs to the printer. Let's just say that's that and be done with it.
That's that!
Inf. That is the end of that! Nothing more can be done. Tom: Well, that's that! I can do no more. Sally: That's the way it goes. Doctor (finishing an operation): That's that! Would you close for me, Sue? Sue: Nice job, Doctor. Yes, I'll close.