Write to p.grabowski.kontakt@gmail.com and a person will answer.
It helps to say which iPhone you have, which version of iOS it runs, and — if something went wrong — what you did just before it did.
My record disappeared. Everything SideQuest knows is stored on your phone and nowhere else. There is no account and no server, so nothing can be restored from ours — because we never had it. Deleting the app deletes the record with it.
The paywall says it cannot load the plans. That is the App Store failing to answer rather than a problem with your purchase. Check the connection and try again; nothing has been charged.
I already paid and the app does not know. Use Restore a purchase on the paywall. It asks the App Store what your Apple Account owns and unlocks accordingly.
How do I cancel a subscription? In iOS Settings, under your Apple Account → Subscriptions. SideQuest cannot cancel it for you and never sees your payment method.
Can I get my record out? Yes — the archive exports your whole record through the system share sheet, to wherever you choose to send it.