Consumer affairs - car lease issue

[Sykes]

Hello. I am looking for some advice with a car lease issue. We have used a broker company, who have failed to meet the delivery date for the car twice now, and we wish to terminate the agreement and move forward with another company. However they are holding us to the £600 cancellation charge, which feels completely unfair since we have already waited several months, and have now been told (two weeks before the delivery date) that it will be another two month delay. What's to stop them deferring it forever? Surely we can't be held to ransom if they have failed to deliver any service? Any help regarding this kind of issue would be much appreciated. We have made work and family plans that rely on us having a car from mid September, and would really like to move forward with another company asap. Many thanks.