Complex sentence: The girls (except Hanna) enlists Caleb's help on hacking to A's phone; however, A tries to shut down the phone, but before A shuts the phone, they were able to discover some clues.
Split into simpler sentences: The girls (except Hanna) enlists Caleb's help on hacking to A's phone; however, A tries to shut down the phone. However, before A shuts the phone, they were able to discover some clues.