All of these parameter declarations are within the same loop.
Let me show you the values in the first loop:
Dim sql As String = "" & "INSERT INTO [atzenta].dbo.phones (" & "name, mobile, telephone" & ") VALUES (" & "@Column0, @Column0, @Column0 )"
Using cn As New SqlConnection(ConnString), cmd As New SqlCommand(sql, cn)
cmd.Parameters.Add("@column0", SqlDbType.VarChar, 50).Value = DataGridView1.Rows(i).Cells(1).Value
cmd.Parameters.Add("@column0", SqlDbType.VarChar, 50).Value = DataGridView1.Rows(i).Cells(4).Value
cmd.Parameters.Add("@column0", SqlDbType.VarChar, 50).Value = DataGridView1.Rows(i).Cells(5).Value
cn.Open()
cmd.ExecuteNonQuery()
cn.Close()
End Using
I hope that helps clarify the issue.
Let me know if you have any further problems ^_^