It's always easier to blame the person who has left for the chaos that arises after the employee leaves. No one wants to be held accountable for their screw ups. It's a natural thing these days to blame the other person.
Now, we can look at it another way....you could be flattered that the customers are raising cain about the fact that you are not there making their "regular" stuff.
Take a nice long walk and release this pent up anger for it will do you no good while searching for a new position. Consider the source and let it go.
Good luck on the job search!
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
