Hello Team,

Mithi has a central customer care number to make it easy when you need to speak with our engineers. You don't need to have different contacts for various activities. Contact can happen through a central point.
Having said that, if you want assistance beyond L1 it can be scheduled on a request basis. 

You can mention the same on the ticket or call and the meeting can be scheduled with L2/L3 team.

Please refer to the below link for more details:
https://docs.mithi.com/home/phone-support-policy

Hope this works for you.