Did you go to the offices and see whats there?
How was the tenant paying rent? Has he any contact details for the agent?
Not naming and shaming as yet as I have nothing to gain from that action at this stage.
presumably the tenant has a receipt?
You might just assist in others been completely ripped off. By reporting an actual and definite case you would not be leaving any entity in a lessor position.
They have closed their office!
If so they should have informed the companies office and Revenue.