It certainly looks as though somone, possibly using two IDs, is trying to manipulate the bidding on your auction. Both of the two high bids have been retracted, and were both placed and cancelled within minutes of each other.
We can't see the bidders IDs, only you can as the seller. Whether they have previous form for manipulating auctions we can't tell. It's quite possible that they will team up to bid and cancel bids again close to when the auction ends, to try to frighten other bidders off and get your phone cheaply.
In your position, I would block future bids from both of them, see: https://offer.ebay.co.uk/ws/eBayISAPI.dll?BidderBlockLogin
