Website wont let me buy Heart of Thorns
Have you tried a different browser? Tried clearing your cache? Purchasing through a different device? The page you are displaying should not look like that.
If you are looking to upgrade your current account, have you tried purchasing from within the game? Tried purchasing through the link above on this page?
If you continue to have difficulties, you can contact the CS Team via the ‘Support’ link above/below and ‘Submit a Request’ for assistance.
Good luck.
I see you have addons like Adblock and stuff, I would also suggest turning them off temporarily for that page, mainly those addons supposed to block Javascript. Possibly the page uses Javascript to complete the process and being denied to use it just causes the page to reload in a few cases.
Had a similar issue with Firefox. I had to use IE to buy HoT.