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

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....
Can I change my invoice payment method?
Yes you can. You will need to do it from your account details screen...
Do you offer TCP and UDP OpenVPN connections?
Yes, and we provide several ports for each type of network topology we offer.
What if I cant find the answer I am looking for?
The first place to look for answers is our knowledgebase. Use the search feature to look for an...
What methods of payment does LiquidVPN accept?
We accept the following currenciesPaypal, Credit Cards, Cash, Bitcoin, Litecoin, Peercoin,...