// in the viewdidload
NSUserDefaults *uDefaults = [NSUserDefaults standardUserDefaults];
    if ([[uDefaults stringForKey:@"Call Alert"] isEqualToString:@"On"]) {
        _callConfirmationSwitch.on = YES;
    }
    else if ([[uDefaults stringForKey:@"Call Alert"] isEqualToString:@"Off"]) {
        _callConfirmationSwitch.on = NO;
    }




- (IBAction)switchingCallConfirmation:(UISwitch *)sender {
    NSUserDefaults *uD = [NSUserDefaults standardUserDefaults];
    if (sender.tag == 0) {
        if (sender.on == 1) {
            [uD setObject:@"On" forKey:@"Call Alert"];
             NSLog(@"switched on");
        }
        else if (sender.on == 0) {
            [uD setObject:@"Off" forKey:@"Call Alert"];
            NSLog(@"switched off");
        }
    }
    [uD synchronize];
}