Gmail — g-mail account hacked

my id [protected]@gmail.com was hacked by some one and threatening with that details plz help me by these. usually this account is concted with [protected]@gmail.com and forwarding option is activated in this account ([protected]@gmail to [protected]@gmail.com). these two acconts are used as one account. plz take necesary action against those who hacked this account: myself swarajkrishna mobile: [protected] account hacked on sunday 19th April 2015 at 5.00pm and 6.00pm plz help me by finding this person and take suitable action against him for our mental torchering.