The following phone numbers are available to Market Pay customers for major incident purposes. 

A major incident is defined as:

All end users (cardholders) are unable to use any part of the system.

or

All of any one customer is unable to use any part of the system.

or

Impacting all transaction flow steadily or intermittently

Regular incident support and service should be obtained by creating a request here: https://assist.market-pay.com/hc/en-us/requests/new