Someone at a community group I'm in messed up playing with Azure through their free for non-profits offering^. We were out about 1.2k€. Not huge but huge for us.
Encouraged by comments on HN over the years I had them ask support to kindly to wave it. After repeating the request a few times they eventually reduced their bill to <100€ but refused to wave it entirely.
So even without shaming on social media, But it probably depends. It's worth at least asking.
^The deal changed about six months ago.
It's waive, not wave