Combobox

I'm having trouble with my combo box which was created using the ActiveX controls. The reason for wanting to do this is I want the combo box to be able to capture the values in range when the spreadsheet is updated without having to manually updated the listfillrange everytime

Code is below, and the red highlighted line is where the error is occuring


Private Sub update1()
Dim i As Long
Dim col As Long
i = 1
col = 1
With combox1
Do Until Cells(i, col).Value = "Totals"
.ListFillRange Cells(i, col).Value
Loop
End With
End Sub