Consider now a self-service gasoline pump. The user approaches the pump and the screen interface asks the user "pay inside/pay here". If the user selects "pay inside" and it is before 10 PM, the pump activates asking the user to go through the gasoline selection/pumping process. If it is after 10 PM the pump signals the store attendant who must release the pump before the user can pump. The store attendant may release the pump or require the buyer to come in and "prepay". In case of a "prepay", the attendant sends the pump the amount prepaid. If the user selects "pay here", the pump asks the user to insert their card. It then asks the user if it is credit or debit. If a debit, it asks the user for the PIN number. After receiving the PIN number or an indication of a credit card, the pump calls the credit card co or bank to assure the user account is valid and that the user has a credit of at least $50.00. Finally, on either transaction (pay inside or pay here), the pump asks the user if they want a car wash. There are two kinds of car washes "car clean and car spectacular" car clean costs $4.00 and spectacular costs $5.00. The user presses the car clean, spectacular or no. If yes the cost of the wash is added to the gasoline bill and the pump randomly generates a 4-digit number which is then sent to the car wash unit as a valid number. Even numbers are for car clean and odds for spectacular. If the user's card or debit account is invalid, the card is returned and the interface screen prepares for the next customer. If the card is valid, the pump asks the user to select fuel and activates the pump mechanism. The mechanism monitors the flow of fuel and calculates the bill displaying it for each 1/10 of gallon flow. If it is a prepay with cash in store, the pump software monitors the flow and shuts down the pump when this amount is reached. Finally, when the user replaces the handle, the pump follows this process. If it is a credit or debit card, the charge is sent to the proper account and the user is given a printed receipt. The pump is locked with the start screen displayed for the next sale. If it is a pay Inside, the cost is sent to the inside and the pump is locked.

Draw a UML Use Case diagram of the pump software.

This is what I have so far:

My question is, does this look correct? This is my first time making a case diagram so I am a little bit unsure. Is what I have so far correct or do I need to add or change anything?