Documentation to redesign a support model

I'm trying to find the best documentation to help me redesign a support model for a company. The end users are external customers and the current L1 and L2 teams are more product specialists in their area mind you L1 does make coffee and put out lunch for customers! Do you have anything that could help? 
 

Answer:

We only have documents for the implementation of ISO 27001 (and ISO 22301), and these standards are not specifically designed for a support model, although you can see this template “Incident Management Procedure” : https://advisera.com/27001academy/documentation/incident-management-procedure/, and this “Operating Procedures for information and Communication Technology” : https://advisera.com/27001academy/documentation/security-procedures-for-it-department/, which are related to the IT support (but remember that ISO 27001 is focused in the protection of the information). You can see a free version of each document clicking on “Free Demo” tab.
Anyway, in your case, the standard that I think that can help you, because it is related to the management of IT services (and their support), is ISO 20000. Here you can find information about this standard “What is ISO 20000? Learn why ISO 20000 can benefit your organization” : https://advisera.com/20000academy/what-is-iso-20000/