MNSi Telecom Customer Service Phone Numbers Customer service: 1-888-310-6674 Windsor: 519-258-2333   MNSi Telecom Headquarters Info, Email, Phone number, Website and live chat Information Trading name: MNSi Telecom Type: Private Industry: Telecommunications Founded: Windsor, Ontario, Canada (September 1995) Headquarters: 3363 Tecumseh Road East Windsor, Ontario, Canada   Managed Network Systems Inc. is a Canadian Internet service