Thanks for taking the time to reach out to the QuickBooks Community for support.
Before we begin, I wanted to ask a few questions to clarify some things. Are you using any extra services? For example, QuickBooks Payments, Payroll, etc.? Do you have customers paying invoices online? Have you received any emails regarding the charges?
While I await your response, I've gone ahead and included some help articles that cover different fees in QuickBooks Online below.
I also wanted to mention that you can contact our Customer Support Team at any time. This way, one of our customer service agents can review your account in a secure environment and investigate the fees for you. The agent can let you know what the fees are for and why you're being charged. I've included the link to connect with an agent below.