Bad customer service

Store assistants and manager refused to make an exchange even though he could see my till slip on my phn and bank records and further failed to track sales made within 24hrs on their system as they always claim that they are able to. Before that incident I had to pay a bigger price because the prices on the floor were not the "right prices" I took pictures emailed to head offices but no response. To make it worse, when I emailed their head office to report this, they gave a reference number but months later still NO response it's no wonder the staff is so unprofessional because you can't report them anywhere.