Listed on TransUnion for a default I didn't know!

I discovered last Thursday, while applying for a vehicle that I was credit listed by Discovery due to a default amount of R1382 that was not paid to them. Upon enquiry the same day I am told that several letters were sent to me informing of this, however I did not receive them. I wrote a letter to discovery and attached proof of residence to prove this, and requested that the call centre agent go ahead and debit my account for whatever is owing. They said they called my work landline too in November 2014 and never again. The reason for me leaving Discovery is because I left my previous job, which Discovery knows. How do you then try contact me on a number that I no longer have access to?<br> <br> Now today I get a message from some lawyers informing me that my account has been handed over to them and I now owe R1576.89 which I REFUSE to pay. How do you hand me over to lawyers when you have already debited my account? My name is in bad records because if this nonsense. Please can someone deal with this and delist me as a matter of urgency.