Why can't I delete old backed up apps,music,files etc on my micro sd card

[AC Question]

I'm using a Samsung galaxy tab pro 10.1 sm-t520.kitkat edition.iv used the fix kitkate app.my sd card is 64 gb class 10,iv tryed deleting with several managers,also tryed 3 or 4 app shredders. I can copy and paste on the sd card but can't delete,althought the fresh info and apps that iv copyed and paste onto the sdcard,does delete,but all the other info from previus week wont delete,will it does delete but when I close the app I used to delete all my stuff,when I open the app again,all my old files and app backups are back were they were after being deleted,plus could anyone help as I'm tearing my hair out with this problem,thank you.

 

[nahoku]

Have you tried deleting them on your PC (via card reader)?