How to cancel (with "another ID")?

I subscribed to Blokada Plus 4 days ago (July 15th). But when Plus is activated, I cannot use it.
So I would like to cancel et be refunded.
But I don’t undersrand how to do this. In the application, I click on “Résilier cet achat”, then its “Veuillez saisir un autre ID de compte, ou revenez en arrière pour continuer d’utiliser le compte actuel (vous devez être connecté pour utiliser cette app)”
But I haven’t another ID. How to find it?

Thank you

Please always include which platform you are on: Android.

To directly help you the best way possible please provide the following information:

  1. Where did you download Blokada from? direct apk (5.14.4)
  2. Which device do you use? Do you use a custom ROM? Do you know which OS version you are using?
    Redmi 7A with Android 10 QKQ1 2021-05-01 with MIUI 12.0.3

Send an email to with your payment info.

Ok, I sent an email.