Hi, @melissam !
Thank you so much for reaching out to our network and sharing your concerns.
To emphasize, there are no circumstances in which you would be charged more than the aforementioned credit card rate that is applicable to each transaction. In your case, AMEX rates are 3.4% + $.30 for online transactions with domestic and international cards, and that rate drops to 2.4% + $.30 for in-person transactions.
Now, you may be seeing a larger fee depending on varying other factors, besides the credit card rate. Some Shopify Payments processing fees to consider include:
- credit card rates are not returned with refunds
- if you are selling and getting paid in different currencies, exchange rates also apply
- cross border fee may apply depending on country of origin
If you suspect your rate is higher still, then we can definitely help you investigate to see if that is in fact the case. Since this will require secure access to your transactions and store, I recommend that you reach out directly to our Support team so we can log in to better assist.
We look forward to supporting you,