First HR basic information call.
For Coding, the same old load balancer is used to distribute the load to customer support agents. So you have to design API's to initialise with agents, set limits for each agent, assign work to the next agent, and get a list of next agents.
They have Minicom round, which is also out there, and repos are there for it.
For System Design, they ask the Low Level Design, mostly DB Schema of the Chat-Based system, groups, private chat, relay messages, etc, focusing on how you will store them in DBs
Then values Assessment, which is a Behavioural Interview.
The interviewers were very inexperienced. They thought they owned the company. Even being disrespectful during times. They definitely didn't know how to conduct the interview.