Google Playstore VPN application debiting money from unsuspecting people who do not use the App

So, I travelled to Zimbabwe where network was down, and signed into VPN trial version. Sadly it did not work for me, and I deleted the app. R 1 649,99 got debited from my account - showing a year's subscription. I queried this, and the response I got is that I will not get a refund - because the trial version automatically becomes a paid for service? For an App I deleted three days later, which never worked? Could the charge not be for a month or something - why a whole year? This is really unfair, and I really need my amount back.