Technically, there's no rule about talking. Having a conversation isn't the same as mic spamming. However, common courtesy dictates that you should STFU if there's only a couple of people left alive. What I and other admins usually do if people won't be quiet is use a keybind that mutes everyone for one minute.
There is, however, a rule about respecting admins, and telling one to fuck off isn't okay, regardless of whether or not you think he's being unfair. Personally, I would have just muted you for 5 minutes or something, but face's actions may have also been appropriate.