They were forced to cancel other 2 gigs, due to injury of Dave Gahan . More specifically, the singer of this year's unlucky Depeche Mode injured his leg during the band concert in Bilbao on Thursday July 9 and the doctors advised him to rest and not be submitted to pressure and intensity of a concert.
So the last two stations of the European tour of Depeche (Porto and Seville) were canceled. Well, he must have heard many curses in Athens, some of them reached him ... All jokes aside, I hope he gets better and hopefully we'll see him back.
Relevant article