Cash flow simplified. Interstate Billing Service has emerged as an industry leader in managing commercial accounts receivable by providing unmatched customer service at competitive prices. Founded in Decatur, Alabama in 1984 with only 5 employees, Interstate Billing Service has grown to employ more than 130 people. Together we service over 500 clients with annual receivables exceeding $2.4 billion, while handling the billing and collecting of a combined customer base of over 100,000. We offer two basic programs that collect your accounts receivable. Each gives you the money up-front. Both utilize our experienced customer service staff to remove the hassle associated with collecting your accounts.