UberEats failure

Today was the third time that I have ordered something from UberEats that was never delivered. Apparently, the driver, Cassim, indicated that he tried to contact me, but I have not received a call and he did not come to reception to deliver the order as per my instruction. I am extremely disappointed, as this was a birthday gift to a colleague of mine. If anybody knows how to contact an Uber driver, please advise.