HELP - Replace a battery on my IPOD NANO 4th Generation ?

I am having a terrible time finding anyone to replace my battery on my IPOD NANO 4th generation ! I see Youtube videos of how to do it but it's so complicated ! Apple wont do it as they say it is an obsolete product ! My Ipod is like brand new ! I have the paperwork and box...like new . I hardly used it over the years. Any information would be greatly appreciate it ! I don't wont to loose my playlist of songs !!!

Thanks