3 Answers

You have directed your question to the wrong site. This is akaQA,  a general question and answer site.

This is akaQA, we are a worldwide Q & A forum, you are on the wrong site.

Generally, you can continue to add to your cart by clicking on the "add more items" spot on your screen.  
The credit is probably given after you enter the promo code, but you may need to refer to your email for some kind of notification.  I had to call the company recently in order to receive the 15% discount I got for placing my first online order.
Record your order confirmation number and contact the company to confirm the credit you have earned.  
And, yeah, this isn't where that happens, but we like to help.