No, they cannot due this unless the articles of incorporation or other agreements among the owners specifically allow them to do this. Otherwise, 1) you are an owner, so they cannot deny you access; 2) you are not obligated to buy them them out--if you and your partners cannot decide jointly on what to do, one or another of you can bring a legal action asking the court to order that the business be sold and dissolved and the assets (if any are left after paying debts) be distributed among you. They cannot require you to buy them out without a court order unless there is an agreement specifically requiring you to do so.