you can use the following code, provided that the repeating data is in the first
column.
the code  will delete the repeating records, leaving all unique.
you may also use pivot table.

Sub deletedublicate()

Dim Satýr As Double, satýr2 As Double
Dim sutun As Double, sutun2 As Double
Dim hucredeger As Double, hucredeger2 As Double
Dim currentcell As Range


Set currentcell = ActiveSheet.Range("A1")
ActiveSheet.Range("A1").Sort _
Key1:=ActiveSheet.Range("A1")
Do While Not IsEmpty(currentcell)
Set nextcell = currentcell.Offset(1, 0)
If nextcell.Value = currentcell.Value Then
currentcell.EntireRow.Delete
End If
Set currentcell = nextcell
Loop


End Sub

You can use following steps of extracting unique  records:

Go to Data
Select Adavanced Filter
Select Copy to another Location
In List Range Select Column A
in Copy to Select G1
Check Unique Record
Press OK

You should have Customer code  in Column A.