The “charges” you interpret may be not by usage, but instead that the prepaid credits from a year ago, with an expiration time of one year, have recently expired, reported by every credit amount and their expiration date listed except the recent one in the screenshot you provide.
You used 14 cents in the month showing, with the bulk of your unexpired amount remaining.
OpenAI policy is that they don’t do refunds of API credits, and they were willing to design and impose the expiration of credits, the system working as they desire, despite the negative experiences.
https://help.openai.com/en/articles/9047769-can-you-extend-my-credits