If it's any help, I have a ticket issued on 17/08/12 in Tortosa.  I went to the town hall to ask where i could pay.  I was told that the company that has the franchise (SIUT), would eventually write to me.  They haven't yet.  It's pinned on the board in my office just in case but it's now so faded I can hardly read it.  Moral ?  Sit on it.