Telkom Contract Cancellation

My telkom phone contract end date said April 2025, I went to telkom and told the lady that I want to cancel, she took my fingerprints and said the last debit order would be in May 2025. I got debited in June for what?? Why am I being debit again?? I reversed the debit order and now they sending me threatening sms's. You cannot do that. What was the purpose of taking my fingerprints and why am I being debited again? I need to speak to an agent and demand a cancellation letter.