owner of commercial building sells property and wants us out by the day after rent was paid adn we move is that legal?

If he wants you out, before the end of a month that you've paid rent for, he'd better have a court order.

If you were forced out, when you had paid for the month ahead, you need to see a lawyer, who can review all of the facts (quite a bit more than you could put here), and give you reliable advice about what to do next.