That's normal. Buyers can't bid against themselves!
It doesn't matter how much they bid, until or unless someone else bids against them they will win it for the starting price. Once you get other bids, the price will rise.
p.s. I've just noticed that you have set a reserve price. If their bids reach the reserve price, this will show. They must have been placing multiple bids in the hope of reaching your reserve.
It's expensive to use a reserve price - you will be charged a 4% fee on this, payable whether or not the item sells. It's cheaper and easier for buyers if you just start the listing at the lowest price you would accept.
