Tsotsi optometrist

I was at an optometrist in polokwana for aviation eye test, the optometrist by the name of Jason Stander, take me to his office and gave me a sit he made me read those letter on a screen, i read the first line and before i could finish he said i need to buy glasses from him, or else he wont give me the form With his signature, my problem is he didnt complete the test and now i have to pay 975 somthing instead of R375, so i feel like it is his way of extracting money from people