The so called global lottery ask me fees to claim my prize is this is real or scam?

i receved email from so called global lottery informing me that my email won $300000 in a free bonus lotto draw they asked me fees of affidavite and opening international bank account .i paid $6000 and sent my my affidavit certificate and my account number in london bank and i log in and found my prize in my account .i try to transfer my prize onlin to my country they asked my a fee of certificate from united nation on drugs and crimes from london with fee $25000 or seize my prize .are this real or scam or what?and hwo we resolve this problem ?if real i can not pay this fee.if scan(not real) how i can return back my moeny paid to them($6000)?