I had it happen three times on the same account including a hidden quota that the UI didn't even list. Sales person said that it might get better if we moved to invoice billing instead of a credit card (why?). After that I just gave up and moved back to AWS.

edit: It's also not a new account, very consistently paying for some services (maps, etc.) for years before I decided to ramp up.

edit2: It was also a tiny quota increase from the default one so not like we suddenly asked for five hundred instances.

Yeah this happened to me recently and it was obnoxious