Outstanding Account

I received a call sometime in March from a lady by the name of Zandalee Goosen saying that there was an outstanding account on my name from the time I hired a car in Nov/Dec. I explained that I had prepaid when i rented the car and did not understand what the account was for. she asked that i sent her the receipt and any documentation so they could see what happened to an email [Email Removed] I sent her the notification from when i booked a car and did not get any response. I then followed up again after some time because i kept getting sms and calls regarding this and that the account had been handed over. the lady that answered my calla said i must sent the proof of payment. I again sent the credit card statement showing the payment to the same email oto Zandalee. and no response still. thinking that the email i had was probably wrong even though she was the one that gave it to me, i sent another email to [Email Removed] telling her that i keep getting calls and i need her to send me a statement so i can understand what the outstanding account is for. I learn now that a default has been listed on my name and i feel this is very unfair.