How much hashing power did he buy in his contract?

If it was something small then it could be possible that Genesis Mining is going to consolidate all the previous payouts into a big payout in the future because the payouts are so small that it's not worth it for them to send it since tx fees will exceed the actual amount/the payout is below dust limit.

But they have indeed received lots of complaints recently and i would not invest in them with my own btc.

Contact their support, and see what they say.