Rain's Unauthorised Debit Order

My Rain debit order went off on 25 July 2021 and on 26 July 2021 I cancelled my Rain subscription, whereby they confirmed cancellation via email. Since the cancellation, my Rain services has been disconnected. I accepted this because of the cancellation. But in 25 August 2021 another debit order for R495 went off from my bank account! This is totally unacceptable. We are living in trying times, living from hand-to-mouth, and then this happens. I am unemployed, but I am trying to start a small 'work from home business' and unfortunately Rain's internet speed was too slow for me. How do I get my R495 back because I did not make use of their services for the month they charged me for