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

Can I change my invoice payment method?
Yes you can. You will need to do it from your account details screen...
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...
What kind of encryption does LiquidVPN use?
LiquidVPN implements the highest level of encryption natively supported by each of our VPN...
How do you handle abuse?
When an ISP sends an abuse report we will post it on our transparency reports along with our...
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....