You can start by going to the payouts page to see if your payout is located there:
http://pool.minebitshares.com/payoutsIf you are mining with X11 I can tell you that payouts didn't go out last night because they were below the minimum threshold for processing. They will certainly go out tonight.
So if it was last nights payouts you are only referring to and it was X11, then this is why.
If there was some other payout the day before you were expecting that is showing on the payouts page, please feel free to contact me and provide all of your details.