Can’t cancel a free trial

Hi:

I downloaded a free trial of a video editor called : video editor ( luni ) it offers 3 days free trial. I didn’t like it and I can’t find it in my subscriptions to cancel it. In three days I’m going to be charged for something I don’t want. When I report a problem None of the choices matches : cancel subscription or free trial . Any ideas how to solve this problem?

Thanks!

leibnyz