unfair legal actions

I had a Cell C Account about 6 years ago, I cancelled the contract due to bad service, but Cell C decided to list me on ITC. Now after my name has been cleared I still received sms's from RL Daly Inc saying that I need to pay my account with Cell C. Upon phoning RL Daly, they had no backup documents or files, they state that they only received instruction from Cell C and that I should take it up with them. We then phoned Cell C and they told me that they would investigate and get back to me. 5 months down the line and I still get sms's saying that I will now be handed over. Why now after 6/7 years is Cell C asking/begging for money and threatening people. I do not have a Cell C contract anymore and I would like them to please stop with the threats. I have no intention of getting a Cell C contract EVER!!!