Wrong glasses

After receiving my new glasses I had trouble focusing on my laptop screen. I went back to Spec-savers Medicross Midrand. I was told that my glasses are single focals. During my original eye test I was asked about the amount of time I spend looking at a computer screen. I informed the optometrist that I spent 90% of my working hours on a pc as well as reading. He then asked me if I would like to have the blue filter on my glasses as it would help to prevent me from getting tired spending so much time looking at the screen. The even treated the glasses to get rid of the glare from the screen. If you knew that it would be in my best interest to have dual focal lenses why still go ahead and make me single focal lenses. You as a professional in your job should guide you clients into making the correct decisions. My question is....why would you make me single focal lenses if you knew that I would need dual focal lenses. The argument came when he refused to accept his mistake and would not help me. He even wrote it down in the file that I spend 90% of my time reading and working on a pc. I feel that it is Spec-saver's responsibility to rectify the problem. I refuse to use Spec-savers in future.