Dishonest- They Charged me R700 for R 100 eye test.

I visited this place to ask about eye-test as they have a big sign on the door which says Eye test R100. Before even explaining to me about this they asked if I had medical aid (why?) said yes and brought my card to show. All of a sudden they were up on their feet telling me about huge AMOUNTS of money that I have to pay up R20 000 for eye test and a pair of lenses. I was cornered and pressured. They eventually decided they were gonna scoop R 700 from my medical aid instead of R100 that is written on the door. That is being dishonest. Today I got a call from them asking me about the lenses I was suppossed to collect- which I know nothing about. That is being disorganized, or is that guilt catching up with you. Coz really will I ever say no to R100 EYE TEST AND ALLOW YOU TO TAKE R 700 INSTEAD??? INSULTING MY INTELLIGENCE LIKE THAT!! TREAT YOUR JOB WITH HONESTY AND INTEGRITY. DO NOT GO SCOOPING PEOPLE'S MONEY. LISTEN TO YOUR CUSTOMER, NO MEANS NO. DO NOT PUSH THEM AND TRY TO HAVE THE LAST WORD IS DISGUSTING