refundable expatriate fees

I had to pay a refundable expatriate fee of R6000.00 when applying for my Nigerian visa. Three of us went to Nigeria on the 1 November 2014, followed the same procedure. One person got their refund and i app**** via email for my refund since i returned to south Africa from Nigeria last year November. There is no other way. I've tried calling them several times and mailing them for my refund but to no avail. They read the emails, divert the calls but not refunding the money which was supposed to be done within two weeks. One person said they not refunding anymore. They have no right to just take my money. I paid a separate fee for the visa. please help me recover my money.