aaa it looks like you've donated to the 14DWY page, not the DLC page ^^; The 14DWY demo is completely separate from the DLC, and you do not need to pay for it. Please read this to learn the differences between the demo, the free version of the DLC, and the paid version of the DLC.
Additionally, donating to the 14DWY page will not grant you the DLC, and I cannot offer download links for accidental or alternative payments. Please read this if you'd like to learn more or request a refund. The FAQ on this page also explains why you can't pay via card.
And just so there's no misunderstanding, are you certain you purchased the paid version of the DLC? If so, please use the download link sent to your email (or the download button on this page) and follow the instructions to install it. If you need help, please let me know!!
