Uber has yet to return my reported lost property..........please help.

On Tuesday, 20 March around 5pm, I was waiting to be collected by an uber driver to take me home. I get nervous in these situations in case I miss the drive, so when I saw a Toyota car arriving, I assumed it was my driver and got in the car. I was expecting Robert and he was expecting Tracey. We worked out quickly that I was in the wrong car as my vehicle was behind him. I swopped cars, but unfortunately left some of my belongings in the wrong (first) Uber car, these included a family heirloom walking stick [as I have a torn tendon] and a scarf. It is impossible to phone Uber, so the next working day, 22nd March 2018, my husband took me to the Uber offices in Airport Industria (Cape Town). We were told that the only way they could assist us is if we have the correct passenger’s cell phone number. I spoke with a very helpful consultant, Mfundo who gave me his cell phone number. I managed to trace the passenger, Tracey, she kindly gave me her cell phone number, which I then gave to Mfundo over the phone, he said yes, he could trace the trip and would get hold of the driver and phone me back. I have made numerous calls to this Uber representative who says he can’t contact the driver any other way and this driver is not responding to his requests. Even though I got into the wrong car my property was still in the hands of an Uber driver and they have done nothing to assist me in getting my property back. Any assistance would be hugely appreciated as the walking stick has a lot of sentimental value that I simply cannot replace and is of absolutely no value to anyone else.