Problems with playback in Walkman

[FedUpZOwner]

I had this issue with my Z, and am now having the same issue with my Z2. When I load music onto my handset (using a 32GB memory card for storage), it starts playing tracks but within 10 seconds or so it glitches and starts playing split-second bits of other songs. It seems to happen after I upload a lot of tracks. 
Does anybody have this problem? If so, any ideas on how to fix it, because what's the point in me owning this phone if I can't use it for music?

[_alexdon_]

Is the microSD fast enough?Try settings-apps-all-walkman,clear data for both apps.Restart.

[FedUpZOwner]

It's a Class 10. Kingston (I believe, I have an armoured case on it and can't be bothered at the moment to unscrew the case to check, but it's not an unknown brand of card). I'll try what you've suggested. Thanks.

[_alexdon_]

Oh,ok,keep us updated.

[FedUpZOwner]

So, I tried as you suggested, loaded 100 songs onto the phone, and within 10 seconds it did the same. It sounds like when you're listening to a CD and you press scan forward. I give up. I have a few other issues with this handset, the annoying one being that it is not receiving calls (although this could be a service provider issue so it's a call to them).
Looks like it's back to the iPod for me.