outstanding amount paid but does not show

i received a sms to say i am R30.92 short paid on my account on 2 april. i immediatly paid R50 onto my vodacom acc cause i need my phone for my work. payment was made 2/4/2015 @ 11:19 am. now i keep on getting phone calls to pay. most irretating voice message with no option to talk to a operator. if you phone the customer care, then they want my whole pedegry. account number etc. who keeps that?????? please stop calling me, cause i am paid in advance. not the first time that i receive such service from vodacom.