Hello! I'm so sorry, this was not intentional. I'm currently updating the pack to V2 and I didn't know changing the price would cause this.I am already contacting itch.io support to fix this as soon as possible and ensure everyone keeps their paid access. In the meantime, please add me on discord (n3cloud) so I can solve this for you immediately.
EDIT: I have just sent an email to all buyers with a direct download link so you can access the new files immediately. Please check your inbox! If you don't see it or need anything else, add me on discord and I'll help you personally. Again, I'm very sorry for the inconvenience!