When you do this:
UILabel *title = [[UILabel alloc]initWithFrame:CGRectMake(0, 10, cell.bounds.size.width, 40)];
[cell.contentView addSubview:title];
You're creating a new title every time and adding it to your contentView. Instead, try adding a tag to your UILabel and changing your existing UILabel's text, like so:
UILabel *title = (UILabel *)[cell.contentView viewWithTag:SOME_NUMBER];
if (!title) {
title = [[UILabel alloc]initWithFrame:CGRectMake(0, 10, cell.bounds.size.width, 40)];
title.tag = SOME_NUMBER;
[cell.contentView addSubview:title];
}
title.text = @"your new text"