Don't use Zebpay,Coinsecure or any other scammy websites for that matter,they are only ripping you off by making you pay 20k to 30k more than the actual value in India(the price is around 20k premium to international market) and also ripping you off by offering 10-20k lower price when you sell
Best way to trade bitcoins is on Localbitcoins(dot)com,genuine sellers and they have escrow function so until you follow everything within the site no scam or cheating can take place
Also it's all about reputation,check the feedback on any trader to make sure he is genuine and reputable before trading
Cheers