I think the guy has probably sent you a faulty screen or it my have been damaged in transit due to improper packaging, both of which are the sellers fault. Get a refund.
Why would you send someone a picture of the LCD working the day you mailed it to them? And the picture could be a old one of when it was working.
Also the lack of response from the seller to your posts asking for help in getting the lcd to work seems suss to me.