Unfair treatment

I took a flight today at 13:50 from East London airport to Johannesburg (flight number FA241). I arrived at the same time as another gentleman at around 13:18 to hand in our luggage since we had both checked in online. The lady at the luggage handover kindly assisted this man but when it was my turn didn't even try to assist me since boarding the flight has not yet happened. Firstly she immediately started speaking to me in isiXhosa which is an awful assumption to make that all black South Africans speak one language where we have 11 official languages. When she eventually realised that I could not understand her, I tried pleading with her to just take my bag through and try to find a solution. Instead, she just told me that I would need to Postnet the bag. As a loyal customer of FlySafair over the last two years, I never expected such treatment from your staff, to say I'm shocked about the blatant rudeness and tribalism from staff members would be an understatement. Please kindly assist with finding a solution to this as soon as possible because I am not willing to pay a Postnet fee for my luggage where as I purchased a ticket which indicates that I am allowed on 20kg checked-in bag and a 7kg carry-on luggage.