To cancel any service,

Email Billing (this will automatically create a support ticket).

please use your email address that you used to order the service you want to cancel (the one on your billing account).

Email contents;
Panel username:
Service to cancel:
Reason for cancelling:

Note: Paypal Subscriptions - please ensure you cancel your subscription in your paypal account otherwise it will still autopay on the renewal date even if your 540hosting service is cancelled.

To cancel the subscription within paypal;
login to your paypal account, find the payment to 540hosting and there will be a "linked subscription" option, select that and then select "cancel subscription".