Unfair payments

Can someone help me please Telkom is the worst I had a contract with them 24months and it ended but because I had been paying the phone even though I lost it .I sent an email asking them that I did not want to continue with the contract. It’s been 2/3years and my bill is 1500 everytime I ask what is the 1500 is for no one gives me answers , but every chance they get they try debiting my account . Am frustrated . Last a lady by the name Sharon emailed saying that I was emailing the wrong department . Why didn’t any of the people who were responding notice that for 2 yrs I’ve been emailing the wrong department and who should take accountability for this mess