Sort tickets on create date if not answered

Since we do have a good amount of tickets; our customer service department handles them from old to new.

If for example a customer sends a message via FB Messenger at 5-8-2020 and om 7-8-2020 he sends the same message again, because the customer thinks he will get a faster reply that way. Since the sorting function works for latest message? - the customer has to wait again untill his message is the 'oldest'

Is there a way to improve this?