Each time I synchronize ankidroid it keeps downloading all the previous media although i deleted them all from ankiweb i even deleted the account and made a new one but nothing changed
Have you tried “Tools > Check Media > Delete Unused Media > sync collection” on Anki Desktop?
(Edit: you can also do that on AnkiDroid; iirc “Check Media” is in the drop down menu next to the sync button)
I did it doesn’t help
Are you sure you are logged on the same account on both devices?
media for which the filename starts by _ doesn’t get deleted
I remember hitting this issue a while ago. You can report the issue to the AnkiDroid developers here: Issues · ankidroid/Anki-Android · GitHub