Ryder here, from the Social Care Team at Shopify. Welcome to the Community and thanks for posting! While we're unable to authenticate your account through social media channels for security purposes, I'd be happy to help you navigate to your bill to better understand where the charges are stemming from.
If you're logged into the Account owner account, you'll be able to locate your bill in your Admin by going to Settings > Billing. Under Recent bills you'll be able to click on any individual bill to find an itemized invoice. You can then compare the invoices to distinguishing what the differentiating charge might be.
Your Shopify bill can consist of the following types of charges: Subscription, Apps, Shipping, and Transaction fees, as well as others depending on what region your business is located in and what types of services you opt-in for. You can learn more about the different types of charges here.
If after reviewing your itemized bill, you're still having difficulty determining where the difference is stemming from, or believe you were charged incorrectly, please open a support ticket with our Support Team in our Help Center by logging in and selecting your shop. One of our Support Advisors would be happy to go through your invoice with you to see what they can find out for you.
Hope this helps! Please let me know if there's anything I can clarify.