Poor service and shifting blame

After my last complaint Specsavers Upington phoned me and indicated that the quote for my lenses was R1 560, but I paid R1 285. My quotation that I have in my possession was only for R1 285. They now indicated that I should pay an extra R750 then only will they fix my lenses. How do you go for an eye test and you're not able to READ or work with the glasses - what does that have to do with the quotation? They now claim that I didn't indicate that I work with a computer - yet I cannot perform any of my duties not only those I perform with a computer I cannot keep the glasses on due to the severe headaches i get from wearing them. I was never asked to indicate what I need the glasses for - my prior lenses was also bifocal, how can I now be blamed for not indicating that I wanted to be able to read of see with the glasses is this not included or the reason why your eyes needs to be tested? Specsavers have left me blind and the personnel are not willing to assist me, but are rather blaming me for this problem.