so the form has a combo field that users can select 5 differnt templates all they need to do is add after -Contact Tel the customers details i want some to prompt if nothing has been added ?
Clearly, we're having trouble visualizing what you are trying to do. In post #5 (not #1) you finally mentioned that you were talking about text selected from a combo. SO, the answer, as with all validation, is to put your validation in the FORM's BeforeUpdate event. That allows you to cancel the save and return control to the user so he can enter the desired phone number.
Code:
If Me.SomeCombo = " blah blah blah" Then
If Me.SomeField & "" = "" Then 'field is empty
Msgbox "Please enter Telephone number.", vbOKOnly
Me.SomeField.SetFocus
Cancel = True
Exit Sub
End If
End If
Not sure if you want to try to determine if the text entered matches the pattern for a phone number but you could do that also.