K850 wrong songs' arrangement in playlist

Hi all!
I recently recieved a K850, which has been used with Orange UK. Now I'm using it in Bulgaria(after debranding with a generic firmware and network unlocking in a supported local SE service center).I should emphasize, that my problem was existing even before the phone's firmware change with a generic one. Now, after I had added my music to a playlist, it became a full mess!!! The songs are not arranged alphabetic, according to their artist's first name, but in a complete mess. Instead of starting with an artist with "A", my playlist starts with Depeche Mode... In addition there are songs of DM and many other artists, which are wrong listed in the middle or at the bottom of the playlist...
How is this possible? Can I manage my playlist to start alphabetic, according to the artist's name like in Walkman phones?
I've always been using Walkman phones & now I'm very dissapointed with that bug of the K850! Even the good old K750 was able to arrange songs properly, without being a Walkman! ...even before I upgraded it to W800.

Thanks for your opinions in advance!