Very dissapointed

I received a refferal note from my doctor for tests that I had to go for and the doctor made a note at the right hand bottom of which tests should be repeated after 1 month. Went I went back after 1 month, without knowing, until I received the bill, they did all the tests again leaving me a bill of R700 instead of R300.00. Ridiculous!! Should I have checked the referral against their paperwork? Not my job!! I will pay for the tests that was supposed to be repeated, but not the rest!! Now I get letters of demands.