Excel Worksheet to Call Modules

So I been banging my head trying to get this to work, it just don't seem to want to call a module when worksheet detects a change. I know it's detecting changes because this error pops up as soon as change is detected. Error picture

Private Sub Worksheet_Change(ByVal Target As Range)
    Debug.Print "Worksheet_Change event fired"
    Dim row As Long
    
    'Check if the changed cells are in column D or F and have been filled
    If Target.Column = 4 Or Target.Column = 6 Then
        If Target.Value <> "" And Cells(Target.row, Target.Column - 1).Value <> "" Then
            'Both cells in the row have been filled, ask the user if they want to run the script
            row = Target.row
            If MsgBox("Do you want to calculate the hours for " & row & "?", vbYesNo) = vbYes Then
                'User clicked Yes, execute the script for the row
                Select Case row
                    Case 10
                        Call Monday
                        MsgBox "Monday has been calculated"
                        
                    Case 11
                        Call Tuesday
                        MsgBox "Tuesday has been calculated"
                        
                    Case 12
                        Call Wednesday
                        MsgBox "Wednesday has been calculated"
                        
                    Case 13
                        Call Thrusday
                        MsgBox "Thursday has been calculated"
                        
                    Case 14
                        Call Friday
                        MsgBox "Friday has been calculated"
                End Select
            Else
                'User clicked No, move to the next row (if it exists)
                If row < 14 Then
                    'Move to the next row
                    Cells(row + 1, 4).Select
                End If
            End If
        End If
    End If
End Sub

All of the modules to call are public, example

Public Sub Monday()
   'script here
End Sub

I've tried a host of things from application run, modules_name = "here", worksheet_calculate then change the script completely to work for worksheet_calculate. I am stumped. All modules are working as intended because I can manually run them and it works. Yes, I did try "Call Monday.Monday" as well.

Update, fixed errors. Still, no modules are being run. Also updated the script to watch for merged cell Pictures are worth 1000 words

Said a wise man

I've made a screenshot of what your module and procedures should look like. It's the same as explained in the comments, but according (not only) to the Chinese, a picture says more than a thousand words:

As you see, it does not matter how to call your module, it's the names of the procedures which matter

Thanks folks, my issue was because of how excel works. If it's targeting a cell with date/time format. Target.Value isn't the right way to approach this. Need to use Isempty(Range("cell")) for this approach.

If Target.Value <> "" And Cells(Target.row, Target.Column - 1).Value <> "" Then
'This is where the issue starts when it's not running the scripts im calling out