Ameren Illinois Business customers may want to be on the lookout for a scam.  Ameren spokesman Brian Bretsch says at least ten businesses have been hit, including one in Centralia.  They are calling Ameren business customers demanding immediate payment of about $500 or their service will be shut off.  Bretsch says Ameren representatives will never call customers asking for immediate payment over the phone.  If a customer is delinquent, they’ll send out a notice in the mail.  He says Ameren employees will work with their customers to work out a payment plan.