United Kingdom  |  Consumer Law

I am an artist who has taken a deposit from a client for two paintings. The client had seen both paintings at an exhibtion. Before I realised the client wanted two of the paintings, I altered one of the paintings (changed it almost completely as I didn't like it). Days later the client confirmed he wanted the one I had just changed. I decided not to let the client know that I had changed the painting and paint another identical to the one he saw at the exhibition. It proved to be impossible. I admitted verbally (not in writing) what I had done. Legally, where do I stand. They are seeking legal advice.