To cancel your subscription click the VPN Administration button on the left hand menu of https://my.liquidvpn.com/clientarea.php 
Click VPN Administration 
Click the service you want to cancel
Click Request Cancellation
Choose to cancel immediately (takes up to 24 hours to process) or at the end of billing period
Either option will stop your subscription before being billed again.

Also Read

What kind of encryption does LiquidVPN use?
LiquidVPN implements the highest level of encryption natively supported by each of our VPN...
What is the best way to do a speedtest?
It is very important when doing a speedtest from a website like www.speedtest.net that you do a...
Does LiquidVPN monitor or log users activity?
We do not maintain any logs on users activity, timestamps, or amount of data transferred. We can...
Can I use LiquidVPN on a mobile device?
The short answer is yes However we have not released our mobile VPN client yet so you will need...
Do you provide OpenVPN configuration files for 3rd party VPN clients?
Yes. We provide OpenVPN configuration files for many different operating systems. You can...