* One provider discontinued the product with a week's notice
* Another provider terminated the account because they thought the account was fraudulent
You cannot build your business based on the assumption that one provider will always be there for you and at the price level you are comfortable with. At some point somehing will happen, and when it does you're screwed if you don't have a plan for switching providers.
Besides what was said; make sure you are not doing fishy stuff. I cannot imagine it was as innocent as written by OP. Hetzner doesn’t just do this; even if you would be running some weirdness, they first tell you and ask what it is. Just like OVH does by the way. Maybe you were hacked etc. Without more info this can be anything and everything and is no cause for concern at all.
I think it helps if your Hetzner account is at least a couple of months old, with usage. Quite often these things happen to new accounts. Lock your server down and monitor resource and bandwidth usage. You don't want to be banned because someone else is abusing your server. I'm on Hetzner too but will consider moving my hot spare out of Hetzner to a different provider.
This might be part of the reason, if OP's account was actually compromised, they signed up this month and got their first abuse report less than half a month after, the type of customer hetzner does not want in general...
Still build on Hetzner. Just build up your architecture without relying on cloud specific services or APIs if possible and once a quarter check if you can rebuild the service on another cloud provider
* A data centre got flooded
* Another data centre caught fire
* One provider went bankrupt
* One provider discontinued the product with a week's notice
* Another provider terminated the account because they thought the account was fraudulent
You cannot build your business based on the assumption that one provider will always be there for you and at the price level you are comfortable with. At some point somehing will happen, and when it does you're screwed if you don't have a plan for switching providers.