Display/Show Custom Error Message

I have a userform with a combobox (cmbSearch) , a textbox (textbox1) and a listbox (listbox1)....and a commandbutton (cmbFind). This userform is used for searching records in my worksheet....where user selects a "Search By" category from the combobox and then enters relevent text search criteria in the textbox....and all the search results are shown in the listbox. This part works fine untill someone tries to search a "non-existent" record. e.g. a customer name thats not in the database and it gives an error. I would incorporate in my code to have a Message box pop up on these type of searches saying "textbox1.value Not Found!" insetad of error message.

Private Sub cmbFind_Click()
Set c = Range("a65536").End(xlUp).Offset(1, 0)
'write userform entries to database
Dim DataSH As Worksheet
Set DataSH = Sheets("ComplaintData")

With DataSH
.Range("L1").Value = cmbSearch.Value
.Range("L2").Value = TextBox1.Text
.Range("N1"). CurrentRegion.Clear
.Range("A1").CurrentRegion. AdvancedFilter Action:=xlFilterCopy, criteriarange:=.Range("L1:L2"), copytorange:=.Range("N1")
End With
lstSearch.RowSource = vbNullString
lstSearch.RowSource = "outdata"

End Sub