Just wanted to post a quick reply because I had this issue but was able to resolve it.
I contacted the support team directly and received a response quickly.
they requested access to work on my website and they were able to update the coding to reflect the discount boxes in the cart page and in checkout.
they had it solved within 3 hours I believe
I wish the solution is posted here too. I am in the same boat and most possibly it is the theme issue. Interested to know more so I can solve this.