In the initial loop, if i choose "y" why does it still loop over again and not move onto the next if statement?

please use JavaScript conditional statements and at least one loop to write a program that satisfies each the following conditions:

If the user tries to get a beverage without placing their cup on the tray, display “Please place your cup on the tray.” If it is the custom refillable cup, display “Custom Refillable cup: Please make your selection.” If it is the custom non-refillable cup AND it is the first time using it, display “Custom Non-Refillable cup: You have one fill remaining; Please make your selection.” If it is the custom non-refillable cup AND it is NOT the first time using it, display “Custom Non-Refillable cup: You have zero fills remaining; Please leave.” If it is not either of the custom cups, display “This is an invalid cup; Please leave.”

    function myFunction() {  
       var haveCup = "n"
       while (haveCup === "n") {
           let haveCup = prompt("Have cup? y/n");

            if(haveCup === "y") {
                haveCup = "y";
            }
    
            else if(haveCup === "n") {
                haveCup = "n";
                alert("Please place cup on tray.");
            }
    
            else {
                alert('I said y or n you dummy!');
            }
    
    
        } 


        if (haveCup === "y") {
            let cup = prompt("What cup do you have? Custom Refillable Cup = crc or Custom Non-Refillable Cup = cnc");
            if (cup === "crc") {
                alert("Custom Refillable cup: Please make your selection.");
            }
            else if (cup === "cnc") {
                alert("Custom Non-Refillable cup: You have one fill remaining; Please make your selection."); 
            }
            else {
                alert("This is an invalid cup. Please leave.");
              }
            }

        let refill = prompt("Would you like a refill? y/n");
        if (refill === "y") {
            cupRefill = prompt("What is your cup type? cnc/crc");
            if (cupRefill === "cnc") {
                alert("Custom Non-Refillable cup: You have zero fills remaining; Please leave.")
            }
            else if (cupRefill === "crc") {
                alert("Here is your drink. Enjoy!")
            }
            else {
                alert("This is an invalid cup. Please leave.")
            }
        }
    }