required to develop a full use case description of the following scenario

The purchasing department handles purchase requests from other departments in the company. People in the company who initiate the original purchase request are the customers of the purchasing department. A case worker within the purchasing department receives the request and monitors it until it is ordered and received. Case workers process requests for the purchase of products under R1,500, write a purchase order, and then send it to the approved vendor. Purchase requests over R1,500 must first be sent out for bid from the vendor that supplies the product. When the bids return, the case worker selects one bid and then writes a purchase order and sends it to the vendor.

NB: Please make sure it is a use case description and not anything else, because this is the 3rd time that i am posting the question, but none of the answers are actually correct. if you need an example of a use case description, let me know because i do have an example