Add unique items in Listbox based on Combobox

Hi,

I have this combobox that is populated by column A.

And a Listbox that was populated based on combobox Vlookup from Column C.

I need to add the unique items in column C to Listbox based on Combobox.

Please see codes below.

Dim c As Range, Variance As String
ListBox1.Clear
With Range("Order_list")
    Set c = .Find(Me.ComboBox1, LookIn:=xlValues)
    If Not c Is Nothing Then
        Variance = c.Address
        Do
            ListBox1.AddItem c.Offset(0, 1)
            Set c = .FindNext(c)
        Loop While Not c Is Nothing And c.Address <> Variance
    End If
End With

Please help.

Thank you.