Premium feature access gone all of a sudden

So in August 2022 I purchased OneCalendar premium from within the app. I was able to use its premium features for a while, but yesterday when I tried changing the color of a calendar, it told me I require a premium license.

When I try to restore the license, it says there is none. But I do see the transaction in my Google Play transaction history.

Why is this happening? I paid and lost what I paid for :O