Unsubscribe

The app does not comply with my expectations. I want to unsubscribe and be refunded.
I tried to unsubscribe within the 7 days trial period, but this seemed to be very complicated. After numerous tries I finally managed but meanwhile I have been invoiced for this app all these months, when I didnt want it and didnt use it. I would be grateful for a full refund.

Eve742589002180 about StarMaker Lite-Sing Karaoke, v5.1.2