Complaint

Good day,I have received tranfer of R250 on Thusrday,then on Friday I have received a call from the lady called Sanelisiwe on ***,she told me that i have received R250 which was transfer by mistake so they need my concern to reverse the money and I explained to her that it was not a mistake that person was paying my money back,she understood and we closed the called,I called the person to ask whats going on and explained to her about the called I just received,she said no they called the wrong person because she made to transfers of the same amount same day so they were suppose to contact the second one and she was still in the branch(Guguletu Mall) the time I spoke to her,and she told me that the phone is on voicemail for the second person and the bank need the concern from that person,so she ended up leaving the branch,later on she told me that she just received her R250 so maybe they got hold of that person,later on the day I ran out of data so I wanted to buy myself airtime form my Capitec USSD,and it said insuffitiant funds,when i checked the balance R250 was gone,and I did receive any notification nor anything,can someone please give a proper explaination as to how this happened