Learna Still Charging My Card After Subscription Cancellation

I purchased a LearnA subscription, but I resigned from it shortly after the purchase. Despite this, payments for the subscription continued to be charged to my card. Today I noticed that payments are still being taken, including charges for August and an attempted charge for September, even though I had already cancelled the subscription and do not use the service. In my view, the August and September payments should not have been charged at all. I request the immediate cancellation of my LearnA subscription as of now and a refund of all amounts taken after the date on which I resigned from the service, in particular the fees for August and the attempted charge for September. I also ask you to confirm in writing that the subscription has been fully cancelled and that no further payments will be taken from my card.