In case you ever decide to return to AWS, its Cost Explorer is far from perfect but it can show you where your expenses are coming from, especially if your costs are pennies. In the last re:invent they even released daily granularity when grouping by resources (https://aws.amazon.com/blogs/aws-cloud-financial-management/...).
I'm back to managing my own systems. So much cheaper and less chance of nonlinear bills.