Did not apply for loan at capfin

On the 16/03/15, I received a call from some agent offering a loan and I told her im not interested,as I was unemployed, on that date received an sms saying I agreed to pay the amount of R300 on the 7th,I did not apply for loan as now I receive ugly smses,called the number 087 but waited for an hour and my airtime chowed,if I app**** when did I receive the amount????? So please rectify your mistake coz I have no business and whatsoever with capfin,how did they get my bank details??? Please investigate