You will find the subtitle button at the bottom right corner of the player, right beside the volume control as the movie starts playing. If you hover on the bubble icon, the subtitles or different languages should appear instantly and you can scroll down to see the subtitle selections/languages. From the subtitle list, you can select the subtitle you want.
Yes, you can cancel your subscription at any time you want. But, remember that, once you cancel your subscription you will not be able to access any content from your website. However, you can browse your website.