very deliberately I bought 2 platinum tickets for ...

very deliberately I bought 2 platinum tickets for the Lionel Richie concert 5 February 2015..there was 100% assured of my seats and seat numbers..for the tickets I paid 225 each .. now I suddenly get a phone call today from ticketmaster that the cards have been declared invalid because something has gone wrong with them in the system and the places have been booked twice !? they offer me other places (worse ones) and a total compensation of 50 ... I do not agree and have said so but they say that I will get the entire amount of money refunded and do not have to come to the concert ... IS THIS STILL NORMAL ?!