Is this legal?

We were suppose to be moving into an apartment tomorrow.
We have paid the security deposit and signed the lease, we were just waiting for the broker to get in touch with us so we could get the keys and give him rent. He phoned us an hour ago to tell us the landlords have decided they don’t want us living there!
We have a 7 month old, we met them at the house, everything seemed fine, he gave us the excuse that they thought we didn’t earn enough money – I’m pretty angry, as to be expected but I don’t know what my0 rights are here!
Does anyone know?
We had hired a truck and all packed to go!