We specialized in Gift Cards & Loyalty store credit solutions.
As said, there it's not possible to add two coupon cods in one order.
With our app you can offer your customer a store credit system - you can reward your customers based on diffrante trigres and actions. your customers can use the store credit they earned as a payment menthod and use it with an additional promo code.
Here is a video with the advantages of store credit.
checkout our listing page and feel free to contact me at firstname.lastname@example.org