Cleaning up after 100X SaaS billing spike

Yes. We have all been there. Someone accidentally backing up logs a little too frequently, running tests a little too frequently etc. The end result is the same: vendor defaults settings and plethora of settings result in an inadvertent huge monthly bill. The damage is done and vendor rep is unreasonable.

So, lets make this unique: You are a small startup with no flex.

Whats your process for fixing the situation ?