If your intention to stop communication - you can block someone.

Or if that's the words that would've been chosen - I would agree to you.

But if you mix those words with extra message, then no. A reply to this new message is warranted.

E.g. if you add a reason and that reason is unreasonable - it's warranted to address that and reply to you. Either do a request without attached strings, or block. Don't write extra conditions/reasoning and then complain that someone doesn't agree with you on those and kept messaging.