Here is a link that outlines all 3 ways:
1-800-681-6192 (Phone)
How do I chat with K12 Support?(Chat) 
How do I submit a support ticket for the ON Products? (Case Central)
Hours of operation: Monday – Friday: 8:30 a.m. to 8 p.m. ET 

Note: If it is before or after hours, we do offer EMERGENCY support for Critical/Down issues such as a School's site being completely down. If your School needs EMERGENCY support after hours, you can call the normal ON Product Support number, 1-800-681-6192 and select the option for Emergency Support. This will route the call to the Emergency on Call person who will further assist you.