The incident happened at about 4.30pm yesterday on Hospital Road after the driver had pulled over.
Officers say the suspect pushed the man from the vehicle – a white Mercedes Vito – before making off towards New Road.
It is believed the thief then turned the van around and headed back towards the Hospital Road area. The van’s registration plate is YF20 ONS.
The courier is said to have sustained slight injuries to his hand and arm.
Now officers are appealing for anyone who may have witnessed the incident to come forward. The suspect is described as white, of thin build, and wearing a black hat, dark coloured jacket and mask.
Anyone with any information should message Staffordshire Police on Facebook or Twitter quoting incident number 0472 of January 11, call 101 or alternatively contact Crimestoppers anonymously on 0800 555 111.