Jury Service Joke

In February i recieved a letter calling me up for jury service just after easter. This clashed with some important uni deadlines so i asked to defer it for 12 months. They then sent me a letter telling me i had to do it in September. Hardly 12 months is it. So if i got a job after graduating this new date was bound to clash with my start date. I did get a job and explained that i had been called up for jury service so arranged to start after it was finished. That all seems fine. Today i got a phone call telling me they have too many jurors and i have two options a) be excused from jury service meaning i wouldn't have to do it or b) stay on jury service. My question is why the hell do they have too many jurors? Do they not think people would make arrangements to fit this in to their schedule? It has really annoyed me that they have waited a week before i'm due to start to tell me this. If they had contacted me sooner i could have changed my plans. As it is i am staying on jury service because i made provisions for it. Bloody idiots. I had better get a decent case!