Fortinet Embedded Software Engineer interview questions

Referred by a formal employee. I applied on web developer but they gave me OA for embedded software engineer and it’s C only. After finishing OA, both recruiter and that employee disappeared. No any following up even though I emailed them to ask for it. I’ve practiced for a few hard coding challenges and review about C but it remains nothing, not even a response. Totally waste my time.

First, it's an online assessment, 10 multiple choice questions and 4 coding questions(which have to be done in C), then a phone call interview, next will be a coding pair interview that lasts at least 2 hours