Hi soggie,
It is common that web hosters have to upgrade their system from time to time and upgrading twice in a month is something common, considering new exploits are discovered from time to time and a solution to overcome it is always a must.

I think you're right, their server seems not responding at this moment. Anyways, they might be performing their kernel upgrade right now? OS patching, control panel upgrading... etc shouldn't give you any downtime.

Just wait for 3 minutes... the server should boot up if that's the case. Just pray for no hiccups or else the downtime might be extended.

Thanks and all the best.