The greatest threat to such exploitation is competition. The more businesses there are competing for customers, the more difficult it will be for any one business to get away with mistreating its customers. The more hoops one has to jump through in order to start a new venture permits, licenses, taxes, fees, mandates, building codes, zoning restrictions, you name it the fewer new ventures will be started. And the least affluent will be hurt the most. The richest corporations can afford to jump through the hoops they have money to pay the fees and lawyers to figure out the regulations.
Small businesses have a tougher time, and so are at a competitive disadvantage.
For the poor, starting a business is close to impossible. So the system favors the rich over the middle class, and the middle class over the poor. In a free nation, by contrast, new businesses would be sprouting up at a rate we can barely conceive, and would be run primarily by the poor and the middle class. No company could afford to treat its customers like dirt, as so many companies do today, because it would be so much easier to start up a rival company that treated its customers better. In addition, the ease of organizing and coordinating a boycott against an obnoxious business is greatly reduced by the capacity for computer networking.