If the internet goes down, Bitcoin is rendered useless, you pretty much can't do anything. But I doubt that the internet will ever go down, as in like fully shutdown across the whole world.
Obviously you cant do anything about your coins if the internet will go down because cryptocurrency is being runned by the internet, but you do not need to worry since internet today is becoming more successful and the bill monthly is very cheap so there is no need to worry about that and focus on working on bounty campaigns to earn more fiat.