Cancelled Service, Still Billed

After submitting a service cancellation (I have the proof) and not hearing anything back, and also not receiving any invoices, I assumed my business with Telkom was done. 3 years later, I start getting calls from Debt Collectors expecting payment for months of service. How can you bill me for a period in which I had cancelled my services and your records will show I did not use the line.

Get your house in order!