Songs not syncing greyed out and dotted circle next to them

I have updated my iPod Touch 5th Gen to ios 8.3 however I have again encountered the problem I had in November 2014.

A large number of songs have not synced from my library to my iPod and are showing greyed out with a dotted circle next to them.

These include albums recently purchased from a site other than iTunes store but also apparently random other songs. The last time this happened

they eventually synced after a number of attempts but this time no such luck.

APPLE SUPPORT PLEASE NOTE THAT I HAVE BECOME EXTREMELY FRUSTRATED AT THE CONTINUED OCCURENCE OF THESE PROBLEMS

AND AFTER SPENDING THOUSANDS OF POUNDS ON PURCHASING MUSIC I AM SERIOUSLY CLOSE TO GIVING UP AND YOU WILL HAVE LOST

ANOTHER CUSTOMER.