"DAY BY DAY" versus "DAY AFTER DAY"

A)
I get fed up with listening to complaints day by day. - WRONG
I get fed up with listening to complaints day after day. - CORRECT

B)
Day after day the pupils are getting more disrespectful. - WRONG
Day by day the pupils are getting more disrespectful. - CORRECT.


NOTE:
Day after day = repeatedly or continously
Day by day = gradually