Yvonne contact your payment provided and check if they have an option where the charges can be paid by the customer directly.
So if the total is 200, and the payment fee by your payment gateway provider is 2%, the customer will be charged 204 directly on the checkout. But the order total will still remain 200 on Foodomaa.
We donot have this on the roadmap planned for atleast 3-4 months where the charges can be directly added to the order total.