Your billing cycle starts on the day you create your account. For monthly subscribers, you are automatically billed once per month on the day that corresponds to your billing cycle. For instance, if you signed up on Feb 3rd, 2000 then you will be billed on the third of every month. If you are a yearly subscriber, you are billed yearly on the day and month of your billing cycle so you would be billed every year on Feb 3rd of each year. For monthly billing, If your billing cycle falls on the 29th 30th or 31st, then in months that do not have that date your credit card is charged on the last day of the month.
If you cancel your account, you can continue to use the service until the end of you current billing cycle. So, to take the previous example, if you signed up Feb 3rd 2000 with monthly billing, and cancelled July 8th 2000, you would have been automatically billed July 3rd (since you picked monthly billing) and could continue to use the service until Aug 3rd 2000). Since you cancelled, you will not be billed in August and you cannot use the service beyond Aug 3rd. If you had chosen yearly billing when you signed up on Feb 3rd 2000, you are billed for a year in advance so if you cancel anytime before Feb 3rd 2001, you can continue using the system until Feb 3rd 2001.
For your protection, your credit card number is stored on our secure servers in an encrypted fashion and even the DrillingInfo staff does not have access to your credit card number. Only the last 4 digits are displayed.