Undelivered package

We ordered a Uber delivery Saturday the 28th in the afternoon, around 15:24 from sunninghill to Bryanston. The people waited for the delivery it never arrived but in the Uber receipt it says package was delivered. We have tried to send message to Uber with no response and have called so many times and keep telling us the email doesn’t agree to phone number when it’s the details I am using. Not sure what to do anymore as the package is still with the driver ans there is no way of getting hold of D Richard the driver.