Updates Item in ListView

Hello Guys Help Me To Count The Item in Listview and Update it.
Scenario..
Customer Buy 3 Milk and 2 Nescafe then the Cashier Punch it
Item-----------------Qty
Milk-------------------2
Nescafe---------------2

The Cashier Forget to Punch the 1 Milk. the Cashier should Punch Another One Milk..But My Code This is What Happen

Item---------------Qty
Milk-----------------3
Nescafe-------------2

Then I want to become like this
Item---------------Qty
Milk-----------------2
Nescafe-------------2
Milk-----------------1

in First row It is Milk then 2nd Row is Nescafe then Third tow in Milk Again..
The Qty, Of Milk Doesn't Updated Because Nescafe Insert Between Them,

If Nescafe Doesn't Inserted Between them The Qty Become 3/..

Just Like What i Mean Sir..

What Should I do ?

Many Thanks Sir

this is my code

Dim Itm  As MSComctlLib.ListItem
Dim X    As Double
Dim Dbl1 As Double
Dim Dbl2 As Double
Dim Aux1 As String
Aux1 = ""
For X = 1 To ListView1.ListItems.Count
  If ListView1.ListItems(X).Text = txtCode.Text Then
    'Qty
    Dbl1 = CDbl(ListView1.ListItems(X).SubItems(2))
    Dbl2 = CDbl(txtqty.Text)
    ListView1.ListItems(X).SubItems(2) = Format((Dbl1 + Dbl2))
    'Total
    Dbl1 = CDbl(ListView1.ListItems(X).SubItems(4))
    Dbl2 = CDbl(lbltotal.Text)
    ListView1.ListItems(X).SubItems(4) = Format((Dbl1 + Dbl2), "###################.00")
    Aux1 = "*"
  End If
Next X

If Aux1 = "" Then
  Set Itm = ListView1.ListItems.Add(, , txtCode.Text)
      Itm.SubItems(1) = txtproductname.Text
      Itm.SubItems(2) = txtqty.Text
      Itm.SubItems(3) = txtprice.Text
      Itm.SubItems(4) = lbltotal.Text
End If