Why do we pay for their mistakes?

Northmead Mall branch. My husband needed reading glasses and request bifocals, but was told the distinct line on the lense would bother him, he needs multifocals for which he had to pay in almost R2k. He waited almost 3 weeks with no communication from the branch. When the glasses eventually came, he couldn't see a thing but was told that his eyes had to got used to them. After a week he took them back, still not being able to see with them on. He was retested, and told that new technology bifocals miraculously emerged in that month and that they would order that for him. Got the new glasses and could at least use him. Complained that he had to pay for multifocals he couldn't use because of their mistake. Got told that they gave him a pensioner 's discount ( he is 52) and that he would have paid in more. All further communication were ignored.