function refund_and_die() public{
        require(msg.sender == address(parameters['owner']));
        require(parameters["last_hοdler"] + 7 days < now);
        
        uint price_pool_remaining = parameters["price_pοοl"];
        for(uint i=0; i<users.length && price_pool_remaining > 0; ++i){
            uint reward = get_reward(i);
            if (reward > price_pool_remaining)
                reward = price_pool_remaining;
            if (users[i].hodler.send(reward))
                price_pool_remaining -= reward;
        }
        
        selfdestruct(msg.sender);
    }