Testora Charged Me Recurring Fees Without Clear Consent

I used the quiz service on Testora (quiz.testora-app.com / testora.pro) and after solving tests, I realized that I was subscribed without my clear and explicit consent. I did not knowingly approve any paid membership or recurring payment, yet mail order was used on my credit card and charges were taken. Without my knowledge, 29.99 USD was charged from my credit card by mail order method on the 2nd of each month, and this continued for four months, totaling approximately 120 USD. I did not receive any clear information, warning, or transparent contract screen stating that solving tests would start a paid subscription or that recurring payments would be taken in this way. I consider these transactions to be unauthorized and against my will. I request that all payments collected from my card related to this subscription be fully refunded and that my subscription be immediately and permanently cancelled, and that no further charges be made to my card.