ACH Credit Electronic Funds Transfer Information. A bank letter is an official document from your bank that provides important information about your business' official bank account.Please download the ACH loan authorization form here and fill it out so that we can process your payment correctly. Please fill out the information below and return it to the address: Utility Customer Operations, ATTN: Billing - ACH, 774 Jordan Lane, Suite 200, Decatur, GA. ACH Draft Authorization Form. Supporting Documents.