No Billing Options During Checkout After Applying Coupon Code

Hello All,

We are encountering a strange problem on our cs cart store. First of all, we are using cs cart ver. 4.2.4

Here's the problem...each time I create a coupon code in the backend, and try to apply it during checkout, the Billing Options section is grayed out in order words there's NO payment options available therefore you can't complete the checkout process. But when there's no code coupon code applied during checkout, everything else seems to work i.e billing options are readily available to complete the checkout process.

In a nutshell, here's what's happening:

Coupon Code applied = No Billing Options, instead you get a link that says "Continue Shopping"

No Coupon Code applied = Billing Options available to complete checkout process.

I have NO idea what's going, and this is getting frustrating not just for me but our customers.

I have attached an image to help illustrate the point.

I have cleared cache so many times and doubled checked the settings on the backend to the best of my abilities, but to no avail.

Please, if anyone can look into this i'd be very grateful. Any tips and ideas are welcomed.