bank wants money back...what happened...

DEPOSITED CHECK TUESDAY MORNING,
WITHDREW MONIES FRIDAY MORNING,
BANK CALLED FRIDAY EVENING WANTS MONEY BACK,
PAYMENT WAS STOPPED BY ISSUER,
SHOULD I RETURN FUND TO BANK AS REQUESTED,
NEED ADVISE...HAVE TO GIVE BANK A RESPONSE...
MONDAY MORNING...
DID I DO SOMETHING WRONG...

I don't think you posted this in the right section, but I can tell you the answer to your question since I worked in banks for ten years. You must return the funds. You are ultimately responsible for the integrity of the check issuer. Basically, you accepted the check trusting it was "good" and the bank is not responsible for the fact that it was not. You will have to return the funds to the bank and then pursue the original check issuer for repayment. You can also hold the check issuer responsible for any bank charges or overdrafts you may have incurred because of this. And my advice, don't accept checks from this party anymore. Good Luck!