Why choose esl power systems? ESL Power Systems, Inc. is 100% employee owned. We take pride in our company and our work. ESL follows a strong set of core values: Accountability, Adaptability, Excellence In Customer Service, Continuous Improvement & Ownership!How do i contact esl customer service? Contact ESL at 585.336.1000 or 800.848.2265, via live Chat Banking, or stop by a full-service branch near you.What are the phone numbers for esl investment services? Phone Mortgage: 585.336.1502 ESL Investment Services, LLC, Support: 585.339.4475 Bill Pay: 800.848.2265 Credit Card: 800.654.7728 Fraud Prevention: 585.336.1140 or 888.353.9920 TTY Line: 585.336.1399 or 800.243.6722What does esl do? ESL builds Ship-to-Shore electrical power distribution equipment for military and commercial applications.