nord vpn sub

I have downloaded a NordVPN just few days ago . They offered one week free trail . But unfortunately it doesn’t work at all in China . I tried several times to connect but failed . So I just simply deleted the app . But later I found that I’m the annual subscription with auto renewal . My question is if the app doesn’t work in China and I’m not able to connect then how I suppose to pay each month . It’s not fair. Any advice will be appreciative how I can get refund and stop paying them for each month . Thank you