Don′t send if email is wrong

Hello!

How can I archieve that a message with wrong email address (misspelling) someone puts in the contact form isn′t send at all.
Instead there should be a “wrong email address” message while the message itself is being kept.

Or alternatively a “wrong email address” message right after typing the email address, before even sending.

I got a “Mail delivery failed: returning message to sender” because a client used my contact form but had a missspelling in his email address. No I have no way to contact him because I don′t know his correct adress and he doesn′t now it wasn′t sent ??