Write to [email protected]. One person reads it, so please say which phone you have and what version of Plant Vault you are on (Settings, at the bottom).
On your phone. If you link a Google Sheet, a copy is kept there too, in your own Drive. Nothing is kept on our servers, because there are none.
Android's own backup carries Plant Vault across, and a linked sheet restores everything anyway. If you are about to change phone and have not linked a sheet, Settings has an export.
Android decides when a sleeping app may run, and Samsung and Xiaomi phones are strict about it. Put Plant Vault on "never sleeping" in your battery settings and it will arrive on time.
In the Play Store: your profile, Payments and subscriptions, Subscriptions, Plant Vault AI, Cancel. It keeps working until the period you have paid for ends. The rest of the app carries on free.
Settings, Your data, Delete everything. It clears the phone. A linked sheet is left alone, so delete that in Google Drive if you want it gone as well.