Mp3 player overwriting & Ghost songs

I have 2 problems with my m250 that I haven’t seen here. I’ve had it almost a year.

Problem 1: About a month ago it’s started overwriting some of my song files. Example: It says David Bowie - Changes but it’s playing Horrorpops - Heading for the Disco. It does this on several of my files.

Problem 2:This week I added a couple of new files and now I find that I have 4 - 10 files of 3 different songs in circulation but they only appear once in my playlist. The assigned numbers will be in a row (95, 96, 97, 98, 99), too.

I’ve tried using the update software and I’ve tried just taking everything off & starting over. Nothing seems to be working. Any suggestions?