REfindly lead generation subscriptions are purchased on a monthly basis.
When you sign up for a campaign, you prepay for a month of service. Therefore, there is not a single date on which you will be billed for a lead generation campaign since it varies in accordance with when you signed-up for the campaign.
You will be billed each month, for each campaign, as determined by date in which you signed up for the campaign. For example, if you sign-up on January 15th, you would not be billed again until February 15th, and so forth.