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

Does LiquidVPN monitor or log users activity?
We do not maintain any logs on users activity, timestamps, or amount of data transferred. We can...
Where is LiquidVPN located and what are your countries logging policies?
LiquidVPN is located in the United States. The United States does not have any logging policies....
Are there any hardware requirements to use LiquidVPN?
A VPN client will run on virtually any semi modern device. It should be noted that the CPU power...
Do you block any ports or types of traffic?
No we do not block any ports out right. Port 25, 22, 21, 23 are monitored for abuse, if our...
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...