Accidently removed ifupdown when updating to ifupdown2. Cant connect to remote dedicated machine, help!

Do you have access to the machine somehow? SSH or a remote console via IPMI/iLO/...? Then you can use the ip command to manually set an IP address to get the network back up to the point where you can install ifupdown2.

There are a few cheat sheets for it that you can easily google.

The most important command in your situation is probably:
Code:
ip addr add <ip addr>/<subnet cidr> dev <nic>
.

For example:
Code:
ip addr add 192.168.1.10/24 dev eno1

You can get a list of NICs with ip a
 
My hosting provider just restarted the dedi and I am able to connect again.

Fucking hell man I nearly got a heart attack.