Is the SLR sold by Elephant Photography Association genuine? Why is the price gap so big?

Because EOS 77D is a new machine, it is unlikely to be refurbished. In fact, there are many routines, not just decoration. As for who you are talking about, I haven't been in contact with it, and I dare not assert it, but there is an old saying: from Nanjing to Beijing, it is better to buy than to sell. All the bargains are taken out of your pocket.