It doesn't look legitimate when you see such a message and someone asks you to contact them on their protonmail email. I know that Protonmail is used for privacy purposes but no company should write you or contact you with Proton email because they are LTD, they have responsibilities and they shouldn't be the one protecting their privacy on that level. Company should be public, open and should be using their own email servers instead of Proton.
So, asking for deposit and contacting on telegram or protonmail was already a red flag.

By the way, I don't understand what happened exactly, was that problem on your router? Or were all of your computers infected? Or was it actually the problem from Freebitco's side?