********s taking off DO without authorization

I cancelled my contract at the end of November 2019, so my last payment would have been on 01 December 2019 for the month of December. On the 23rd I received an sms saying that my debit order for January will go off on 31 December 2019 to which I phoned the call center reminding them that I cancelled and no money should be taken off my account and the lady confirmed that nothing will be taken off. Guess what, they just deducted R424.50 off my account! Planet Fitness - I suggest you call me immediately and also refund me my money immediately or I will plaster your bad services and lies all over social media and report you to the Consumer Goods and Services Ombudsman, do not test me on this, I am livid!