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 use LiquidVPN on more than one device?
Yes, you can use LiquidVPN from as many different devices as you want. The only restriction we...
Does LiquidVPN monitor or log users activity?
We do not maintain any logs on users activity, timestamps, or amount of data transferred. We can...
What support options do you offer?
In order to keep costs down we provide technical support and remote assistance via trouble ticket...
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....
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Because we offer OpenVPN, PPTP and L2TP LiquidVPN should work with most routers. Routers with the...