All of a sudden there is debt out of nowhere

We contacted you repeatedly and you could not find us on your system so we got our clearance certificate and now suddenly you want to call and say you are owed over R40K - how is this even possible and based on what people are saying it probably doesn't exist - you just making things up. There is old paperwork that shows it was under R10K owing many many years ago so how did it go from not reflecting on your system to showing over R40K due. I will not let you rob us like this.