He called dig alert, they let him down which is unusual but not unheard of. Im a lineman and with no USA ( underground service alert) or with a USA the only difference is hand digging with caution. If no power tools are involved he's home free. No dig alert = hand digging with common sense.
See line 8 of US building code service cable depth minimum. So theoretically if they met the "minimum requirements", most utilities exceed, you would need to dig deeper than 18" to even consider hitting it. That being said it's only 120/240 and your shovel handle is likely wood. I wouldn't...