Continuing Debit Order of monthly school fees from Spark School for a child that left the school

I de-registered my son from Spark School. His last month was end of term in June. Spark School still debits school fees from my bank account. My emails to the account department are not being rep**** to.

Worse part is that I cannot even dispute or stop Spark School debit order on my bank app and I am out of the country so I cannot go to the bank branch.

Spark School Account department is the worse.