xcode objective c - when I call 2 methods - only the last called method runs and first one is skipped

-(void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
 {
 
     [self NextHeading]; // this plays an mp3 file
 
     [self NextHeadingMeaning]; // this plays an Mp3 file
 
 }
 

Only [self NextHeadingMeaning] method is called and NextHeading method is missed each time

-(IBAction) NextHeading{ 
     [audio stop]; 
 
     NSString *Filename = [[NSString alloc]initWithFormat:@"CH%@S%@",Heading,Meaning];
     Filepath = [[NSBundle mainBundle]pathForResource:Filename ofType:@"mp3"]; 
 
     audio = [[AVAudioPlayer alloc]initWithContentsOfURL:[NSURL fileURLWithPath:Filepath] error:NULL]; 
 
     audio.delegate = self; 
     [audio play]; 
     [Filename autorelease]; 
 }
 
 -(IBAction) NextHeadingMeaning { 
     [audio stop]; 
 
      NSString *Filename = [[NSString alloc] initWithFormat:@"CH%@S%@",bold**Chapter**bold, Meaning]; 
      Filepath = [[NSBundle mainBundle]pathForResource:Filename ofType:@"mp3"]; 
 
      audio = [[AVAudioPlayer alloc] initWithContentsOfURL:[NSURL fileURLWithPath:Filepath] error:NULL]; 
 
      audio.delegate = self; 
      [audio play]; 
      [Filename autorelease]; 
 }
 

Why is this happening and how can I resolve it ?

Please advice, thanks in advance.

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