Inserting row and deleting row simultaneously. UITableView

So I have a UITableView that represents a video library. The datasource of the library is a NSMutableDictionary that contains a NSMutableArray for each of its keys. Each of the Arrays contains an Array with all the info for each value.

NSMutableDictionary -> Foreach Key a NSMutableArray that contains -> NSMutableArrays.

tableSectionDatais my datasource.

I have been trying to insert a row on the first section and delete another row in another section. This is the code I am using:

EDIT This is the new attempt. I first update the datasource and then add and delete the corresponding rows that are indexed with my dataSource.

[mainTableView beginUpdates];
    NSMutableDictionary *clone = [[NSMutableDictionary alloc] 
                          initWithDictionary:self.tableSectionData copyItems:YES];
    for (NSString *key in [clone allKeys]) {
        if([key isEqualToString:@"Videos available for download"]) {
            for (NSArray *videoArray in [clone objectForKey:key]) {
                if ([[videoArray objectAtIndex:0] isEqualToString:helper.videoName]) {
                    [[self.tableSectionData objectForKey:@"Downloaded videos"] 
                                               addObject:videoArray];
                    NSUInteger insertIndex = [[self.tableSectionData 
                                               objectForKey:@"Downloaded videos"] 
                                                        indexOfObject:videoArray];
                    NSIndexPath *pathToInsert = [NSIndexPath 
                                         indexPathForRow:insertIndex inSection:0];
                    NSArray *indexesToAddition = [NSArray 
                                                    arrayWithObject:pathToInsert];
                    [mainTableView insertRowsAtIndexPaths:indexesToAddition