They didn't pay a transaction fee and they funded the transaction with bitcoins that they had received only 1 day earlier.  This puts the transaction pretty low on the priority list for the miners.  There is a chance that it will get confirmed later today, it will most likely get confirmed sometime in the next few days.

I would recommend informing them of their mistake and not using their service until they learn how to properly create transactions that will confirm quickly (such as including a transaction fee of at least 0.0001 BTC per kilobyte).