[piotrkulpinski]

Here's a list of open source alternatives to switch to: https://openalternative.co/alternatives/opsgenie

Most of them can be self-hosted so you won't be locked in in case that happens again.

[jjtang1]

Who alerts you when your own alerting system is down?

[johanbcn]

You set up another alerting system to watch the alerting system. Duh!

[rellid]

Self hosting your alerting tool seems like madness to me, but, you do you.