Your objects and keys are in the wrong order:
NSDictionary* finalData = [[NSDictionary alloc] initWithObjectsAndKeys:@"index", [NSNumber numberWithInt:i], @"myKey", feedData, nil];
It should be:
NSDictionary* finalData = [[NSDictionary alloc] initWithObjectsAndKeys: [NSNumber numberWithInt:i], @"index", feedData, @"myKey", nil];
Or even better, using Objective-C Literals:
NSDictionary* finalData = @{@"index": [NSNumber numberWithInt:i], @"myKey": feedData};