Scheduled maintenance on their network, notified 1 week in advance. "No action required", they said. My IPv6-only VPS stopped to be reachable from outside and I could not get the web console. I opened a ticket and after some ineffective suggestions (trying to switch the machine on and off or go into recovery mode) as I was sure there was a problem in their new network, I found a workaround by myself: buying a floating IPv4 address, attaching it to the machine and using Cloudflare for IPv6. Today, after 16 days since the high priority ticket has been created, I got a reply with a solution: create a new instance, one month of refund.
Tip: there are many good alternatives to be considered even if you are looking for <= 5 $ VPS that have way less shortcomings and many times the cheapest VPS on Scaleway is above 10 $/month because of prolonged shortages. I would consider it only for hobby projects which require a lot of network traffic (VPS network is not capped).