Won theme park tickets

We have won tickets for a theme parked and specified telephonically that we could only go on the 7th june and we did submit the booking forms in may already i gave 3 dates and then i called to cancel the one date a guy cant remember his name said that its fine and that well be receiving feedback wednesday 4 june and that i will then have to go to computicket to claim the tickets. NOW i phoned them and said i havent received feedback as yet and spoke to Doreen and she told me sorry we cant go this weekend for they have reached their quota and is fully booked for the next 3 weeks and that we have to go another weekend. we too have other arrangements and this was why we could only go this coming sunday 7 june. This is pathetic and so disappointing of mcdonalds. why should we ever buy from them again. never recommending mcdonalds to anyone again!!!