Trapped pigeons in abandoned building!

Hi there i need your help. There is an abandoned building near my building block for quite some time. Several days ago i noticed the pigeons finding a way in, so i thought a lot of them might have go in. One day i noticed the agency people that sell the building inside and there were many birds flying around. I thought they would open the windows to let them go. To my dismay they properly closed everything off and left!! There are around 60 pigeons inside! I am aware of the law for trapped birds and when i called the agent to come free the birds he was extremely rude and started arguing with me that they have an access to come out!! But they dont. I manage to break in through the door and i opened couple of windows, but now everything is closed off and they have closed the door properly so i no longer can help. Could you please advise me on what should i do? This is not 1 or 2 birds but over 60 as the building has 3 storeys! Look forward to your prompt reply!
Regards, Ina