How can I use a coupon code as a flow filter to find who hasn't used it?

Hi, 

We’re using WooCommerce and have a Smart Coupons plugin active in which it generates a 10% discount coupon for customers who purchase a certain product. 

This coupon is automatically applied their order confirmation email, but a lot of customers are missing the coupon. 

We’d like to create a flow in Klaviyo that does the following:

1. Triggers a ‘reminder’ email 14 days after the product has been purchased
2. Reminds the customer of the discount code
3. Is able to know if the customer has placed an order in the past 13 days using that discount code

The third section is where I am stuck. 

I can configure a ‘conditional split’ that can filter through customers who have placed an order for a product in the past 13 days for a specific product…

...BUT is Klaviyo able to filter through customers who have purchased using the discount code? 

Here is what I have set up:

This conditional split doesn’t specify if the order placed used the discount code, so could be sent to a customer who has used the discount code in the past 13 days. 

Any help/advice on what could be done? 

Many thanks,

Stefan