He hasn't confirmed yet.

P.S. The startup is pretty big now as it has millions worth of funding.

Most people are very busy. It helps to remind yourself in these situations that you don't matter (and I mean that respectfully and empathetically). Often it will take my clients 1-2 weeks to come back to me even though they say "they need my services right away".

Steli from close.io talks about making SaaS cold calls/emails for 5-7 times until he gets a positive reaction, unless told to F.O. People are busy.