Promoters seeking cash - plus interest - after non-payment
Singer was due to play fundraiser for George Michael-founded art group in Dallas
Purple one plays greatest hits at Izod Arena
Singer will hit the road with a host of new artists including Janelle Monae
Singer promises shows will be 'funky'
Singer shuns downloading for new album '20Ten'
The National, Kasabian and Pavement also perform on the last day of the 40th anniversary of the event
Singer to play Roskilde, Werchter and Arras events<strong></strong>
Incident relates to cancelled 2008 Croke Park gig