The price difference you're seeing may be due to the seller's shipping fee if this item is fulfilled by the Merchant (usually applied when the seller is not FBA).
However, there could also be an issue with the code and you are welcome to reach out to the seller to find out why.
You can find a contact option in your Jump Send account, next to the product on your
Selected Deals page you will see a "Contact" blue button if you click on the menu when you click on the arrow next to Confirm Purchase:
That should open a new window redirecting you to your Email service but if it doesn't, you can also right-click on the Contact Seller button and it will give you the option to Copy email address so you can then send the email manually: 
Or find their email either in the email you received about being approved and where you got the promotional code.
We highly recommend you contact the seller and let them know what's going on. We are trying to encourage communication between buyers and sellers as much as possible, since sellers have to be properly vetted before they can run any promotions now...and they should answer your concerns or problems in a timely manner.