Most of what we found so called "top exchange" are not true sometimes. Based on my experience, some of them are den of bots and crappy things that spam the exchange to fake the volumes. So you have it experience them yourself. P2PB2B is an example for that. What funny is they claim themselves as one of the best exchange out there. Try Binance or Houbi, good exchange and been operating for a long time. Also list only good altcoins in the market.