The cycle usually ends at the end of every month, so the 20th day of the proceeding month is when the payments are usually released.
Remember, these payments are based on your "Current Balance" and not your Total Balance. There are thresholds (I think $100) that need to be maintained in order to be accepted for a sale.
Also, more often than not an advertiser would want to check whether your leads/sales are authentic and ensure that there are no chargebacks or anything. This happens especially if you're a new publisher or if you share little to no history with the advertiser.
I'd recommend waiting till the end of the month when you complete your NET30 and if by then you see nothing, you can write to their support in the first week of the next month.
Net30 Payments trouble you only in the first month. After that money starts rolling in like clockwork every 20th and it's a smooth sailing ship from thereon.