Since it's unlikely that anybody would enter a 10 digit number *except* for a phone number, maybe you could do this:
txt = "I want 30 pounds of butter and 12 pounds of flour."
Set re = New RegExp
re.Pattern = "[^\d]"
re.Global = True
If Len( re.Replace( txt, "" ) ) > 6 Then
... reject message ... has 7 or more digits in it ...
... has 6 or few digits, so not a phone # ... it is okay ...
You can decide whether to use 6 or 9 or whatever as your cutoff point.