Inconsistent treatment of pregnant women

On 13/12/15 my son and I were to take a flight to Cape Town from Lanseria. At the check in an adjacent counter staff asked the staff attending to me to ask me how many weeks pregnant I am. I was 29 weeks & was informed I needed a drs note. I was asked to obtain an email from the doctor giving consent to fly with the practice no. This was unexpected as other airlines only require this after 32 weeks. Although my dr was on leave, he sent an email to me. When I presented it to the staff they then said it requires the letterhead. The doctor then spoke to the staff on the phone to explain that it was impossible to acquire the letterhead now on a sunday as he is on leave and I was denied boarding. Ivwas extremely inconvenienced and distraught. I was forced to change my flight to the next day and was ********** of R1600 and had to drive 120km back home. The next day at check in I received my boarding pass and when I presented the note it was just glanced at and given back to me. When I told him I had to change flight from the airport prev day just to obtain this then he asked a colleague about protocol. The staff are oblivious of protocol and inconsistent & un accommodating. Unfair