Harassment from Shapiro Shaik Defries Attorneys.

I was handed over to these attorneys for a Cell C account that ended in 2018. After numerous requests to them to provide me with the documents on which they are basing their 'Debt Collecting' NO response is received....YET they can call me every single day regarding this matter. This is extremely traumatizing and emotionally stressful. Why can't they simply provide me with the documents on which they are basing this order from Cell C? I have sent numerous email to ask for this without any response.