I'm under a huge d-dos attack.

In order to circumvent it I need to apply changes to the server.
I've never had problems due to using sucuri as reverse proxy, worked great, they had server issues lately so I went and started using CloudFlare instead, which helps nothing.

So I'm under attack, and whenever the attack happens DigitalOcean starts null-routing my server, which makes it impossible for me to apply any changes at all. They keep doing this for 3 hours and automatically stops it, but before I can get to apply any changes they start null-routing again due to the d-dos hitting again.
And this just keeps going on forever in a loop and I can't do anything.
I can't even backup my files or sql database.

I just want to adjust the iptables so only my anti-ddos reverse proxy is the only thing allowed.

I have 1000 customers right now unable to use my software, and have no new buyers, loosing money for every second.

I'm stuck, wtf should I do?