Since GOD never has been SEEN or HEARD what matters if he EXISTS or NOT?

Since oxygen never has been SEEN or HEARD what matters if it EXISTS or NOT?

You cant see or hear a small pox virus, what does it matter if it exists or not?

Indeed. There is no practical difference.

A - You cannot POSSIBLY know
that God has never been seen or heard.

B - Black holes have never been seen or heard. Does it matter if they exist?
(Etc. several other things known or believed to exist.)

Try using the same logic with air.

cause he does exist and sees and hears everything

God has been seen AND heard. His existence is unquestioned by those who saw Him, and still hear Him. 

God is.. The Absolute Truth.. The Supreme Soul. He always resides deep within our soul..and guides us in mysterious ways..

Answered in Hebrews 1.

Some dude or dudette tells YOU that some GOD wants you to inflict HARM on someone, or that some GOD wants you to make a donation to somebody's pocket, it SHOULD make a difference if there actually IS a GOD which wants you to do either.
BUT-- if it DOESN'T, then verily, I say unto thee, GOD hath revealed that you are supposed to send me a bank draft worth one-half of the total value of all your possessions.
Amen!