Singer is seeking to leave the label following rape allegations involving her former producer
Sony says it's legally unable to release Kesha from her deal
Gaga has written about Kesha's legal battle with Dr Luke and assault allegations on Instagram
Organisers say "It is important for Sony to see the uproar they have caused"
Singer is seeking release from her contract with former mentor
Video footage from 2011 shows Kesha denying that producer drugged and raped her
Singer promises to release statement soon
'Girls' creator writes open letter about pop star's legal case with producer and label boss
Producer has been accused of rape by the singer
Bleachers hitmaker also brands Dr Luke "a creep" on Twitter