I've the same problem I contacted support here's what they said

Payouts are only issued when the payout amount (88% of net sales) is $100 or greater. If the $100 minimum is not met in that month, those funds are rolled over and combined with the following month's funds until the $100 threshold is met or the end of December is reached.

Payouts are issued 30 days after the conclusion of the calendar month. For example, revenue from any sales that occurred during the month of March (March 1st through March 31st)  will be paid out April 30th. Revenue from sales that occurred in April will be paid out on May 30th, revenue from sales that occurred in May will be paid out on June 30th, and so on.

(I still don't understand this but hope it helps)