Annual Subscription Cancellation

I purchashed a sketch up pro annual subscription a year ago , but being not that genius with the technology overall , I didn’t realize that the subscription has auto-renewal . So I ended up purchashing it again today , but I have not use at all sketch up the last 6 or more months , because the software is not fitting my needs . Also for me 300 USD that I spent for something that I will not use is a great deprivation . Can someone help me ? Thank you for your time .