What is the most logical next event?

How to complain about your hotel stay
Contact the person at the front desk.
Your first step in complaining about a hotel stay is to talk to the person at the front desk of the hotel. This person will serve as your initial point of contact for lodging a formal complaint or seeking some sort of rectification.

OPTIONS:
(A). This person must be at the front desk when you start complaining about your hotel stay. Some hotels charge by week and sometimes even month..
(B). You can visit a vending machine and ask this customer for a receipt. Contact this person to let them know that they have provided you with this receipt and that they still have it..
(C). You can do this during or after a hotel stay. Approach the front desk calmly and politely..
(D). This person can be a friend, an assistant, or even an employee at a hotel. If you call the person and the receptionist asks whether you need more details, answer briefly and ask about the hotel stay..
(C).