Disappointed

I had a contract with Telcom on wifi_ my contract ended and I done month to month, in August the 15th 2021 I canceled the month to month, paid the last payment in August 31st, received an email which said thank you and was final payment, then end of September they took money again, I reversed that payment as I know I don't owe then, I phoned logged a complaint, still got emails that I owe, December I physically went in to a Telekom store, showed my bank statement, they saw I paid August, she attached the statement to my case number_ today they deducted money again from my account