Usually things goes pretty smooth for me, but this just happened.
Someone rent for 3 hours. Renting start, but the miner don't switch on Betarigs, meaning that the pool chosen by the renter isn't working. Live stats by CGMinerMonitor show all is good on my part. I send a message after 5 minutes, explaining, recommending checking config and trying another pool, and offering assistance. Then again after 20 minutes, and after 1 hour. No answer.
Now I just imagine what will happens when the renter will be back / notice / see the messages...

Added:
All good; renter later replied and paid regularly.