Please stop telling me I owe you while you can't tell me what it's for

Good day again

Please assist

I am still having an issue with cell c debiting me for a contract that is supposedly now cancelled, they have now sent my details to a third party, no one has boadered to call and explain why I owe 870, what is this for, a third party who keeps calling me every morning at 7-8 and everytime I ask them to send me all communication with relations to cell c in writting, I received nothing until today they telling me I'm being charged intrest for what?

What is going on here?

I sent an email last week asking for clarity no one could help, again I'm being kept at debt by the organization. Please explain why I owe so much money qnd why was my details given to the third party?

Since May I have been waiting for a senior person to contact me , that has not happened till today but somehow I owe money and it has interest.