If you require to cancel your VPS for any reason, you need to put in the request by logging into your account at https://billing.chicagovps.net, going to products/services, and then select the particular item you would like to cancel. Then go to management actions > Request Cancellation.
All ticket requests to cancel any service will be directed to put in the cancellation by logging in.
If there is anything that we can help you with before cancelling or if you need a different service to better fit your needs, please open a ticket with sales. We would be happy to help you.