I Need a Refund for an Unexplained Testora Subscription Fee

I have a subscription with Testora, and on 05.05.2026, an unexpected charge of 25,74 € was debited from my account without any understandable reason. Before this date, I had not been informed of any price change or additional costs and I therefore consider this debit to be unjustified. I have not yet contacted Testora customer service, as I would first like to have the matter clearly documented in writing. I request that the amount of 25,74 € be fully refunded and that I receive a clear explanation of why this amount was charged. I expect the issue to be checked as soon as possible and the unjustified charge to be reversed without further delay.