Told that I am 1 minute late

On the 11/08/2015 I was suppose to take the 16h20 flight from OR Tambo int. to Cape Town I did everything on time including Checking in. I checked in at 15h40 then I went to buy myself something to eat. I came back at 16h05 then I was told that I'm 1 minute late I'll have to take another flight. I didn't have any bags with me and I was told I'll have to take the next flight which will depart at 18h30 and I need to pay R400 in order to be on that flight. I did pay that R400 which was my last money now I don't have money to go to work. What I want to find out from mango is that why didn't they let me in because I did everything on time including checking in on time. Only thing is I got lost while trying to find gate C10. All I want is my R400 back because the way they treated me was unfair and a ****************. I would understood if I didn't check in on time and in my case I did everything on TIME its just that at Gate C10 I got there 1 minute late according to those consultant at the gate. Can mango give me my R400 back so that I can be able to go to work please. <br> <br> Cell number: ***