Just Property lease agreements

Please be very cautious when signing a lease contract wirh Just Property. Due to circumstances I had to cancel my lease earlier than the 1 year agreed on. On my contract the 'fines' for breach of contract were stipulated and I was fully prepared to pay. They however charged an addisional 'penalty fee' of 2 months rent , not stipulated any where on the contract. So....something to be aware of !