Hey satishstock,
Welcome to The Game. I think you just got a whole brick of info dumped into your lap, but if you get confused, investopedia, finra.org, and even good ole fashioned Wikipedia can help you learn all you want about the ins and out of dividends. But for the most part, you won't see your actual money in your zecco account for some time (average about 3-4 weeks). When those dividend payments are delivered, then it will show up on your account history, so don't worry if you don't see it immediately.
And as per your main question, the zecco "trading power" and "buying power" numbers are slow. They don't update right away, and even then they can be a little off. But if the Sell trade is executed, your money is available to you to re-invest right away. By the start of the next investment day, all your balances and buying power numbers will be right in line with your actual amounts.