What does fastfast enterprises do? Fast Enterprises, LLC is an industry leader in the development and installation of software for government agencies. In 1998 we forever changed the way government revenue agencies support their business with the introduction of GenTax®. This commercial off the shelf (COTS)...How do i contact enterenterprise fleet management? Enterprise Fleet Management. 1-877-233-5338; Maintenance Program Information. 1-800-325-8838 What is the phone number for enterprise customer service? Customer Service. 1-855-266-9565; Roadside Assistance. 1-800-307-6666; Enterprise Plus® Member Services. 1-866-507-6222; Customers with Disabilities. 1-866-225-4284