Hate to disillusion you - but exactly this happened to us on AWS a couple of years ago. 1 months research compute - no biggie, but no more AWS for us either.
For smaller users I can imagine this sort of thing happens pretty regularly with every cloud, even smaller ones.
Please reply if you had a TAM and were spending that much! I'd be personally interested to hear that was the case.
They offered to investigate if we paid for support, I counter-offered with not using the chat script in one of my courses as an example of AWS customer "support", and we ended up getting a full refund at least.