It's still crap though. If they spin up an instance billing $1k a day you'll find out after they've already billed several hundred, if not at least $1k. There needs to be a way to set actually limits, not alerts. You should be able to say "I'm not using this service, the limit should be $0."
Of course, if OP didn't have MFA / let their keys leak this may not have helped anyway if the hacker was able to just remove the limits.