I want to get my payment back.

Hello @Fiona29858883x5cx,

I hope you are doing well. I am sorry for your experience with Acrobat Reader Mobile.

Since Acrobat Premium is a mobile-based subscription, I suggest you contact the store from where you purchased the subscription.

You may refer to the below links for more.

For Android

Our help article to learn more:  Subscription Services — Acrobat for Android Help (adobe.com)

Initiate refund from the store: Request a refund on Google Play - Google Play Help

For iOS 

Our help article to learn more: Manage subscriptions — Acrobat for iOS Help (adobe.com)

Initiate refund from the store: Request a refund for apps or content you bought from Apple - Apple Support.

Let me know if this helps.

Thanks,

Souvik.