Excel plots disappeared, need them back

Open VBA editor (press Alt+F11) Hit Alt+I, M

A gray before part of VBE shall become white - paste there a code:

Sub test()
Dim msg As String, wks As Worksheet, i As Long
On Error Resume Next
ActiveWorkbook.DisplayDrawingObjects = xlDisplayShapes
DoEvents
For Each wks In ActiveWorkbook.Worksheets
  msg = msg & wks.Name & " - " & wks.ChartObjects.Count & vbLf
  If wks.ChartObjects.Count > 0 Then
    For i = 1 To wks.ChartObjects.Count
      wks.ChartObjects(i).Locked = False
      wks.ChartObjects(i).Visible = True
      wks.ChartObjects(i).Activate
      DoEvents
    Next i
  End If
Next wks
ActiveWorkbook.DisplayDrawingObjects = xlDisplayShapes
MsgBox msg
On Error GoTo 0
End Sub

It will try to switch on displaying shapes, and change visibility of plots one by one, and at the end display summary how many (despite visible or not) plots are there in workbook.
If you get the list of sheet names all with 0's - the plots are probably lost. if there are numbers - they are there just invisible (or may be now already visible?)

Sorry to hear so.
What format have you saved it? Wasn't it csv?

May be somebody else will have other idea, but from my experience - 0's in the message box mean: there are no plots in the file