Unauthorized Nebula App Charge After Free Trial

I only selected the two-day free trial in the Nebula app. Even though no active subscription appeared in my account, I received an SMS from İş Bankası today at 2:24 p.m. stating that $15 had been charged to my account and that another charge of $45 had been attempted at the same time. The bank blocked the $45 transaction for security reasons, but the $15 charge was successfully processed and appears on my account.

At the time these transactions occurred, I was not using the app or my bank's mobile app. I had only signed up for the free trial previously and then completely deleted the app. Despite this, my card was charged with the description "thenebulaap," and another charge was attempted without my knowledge or authorization.

I am requesting an immediate refund of the unauthorized $15 charge. I also demand that any membership or subscription associated with my account be canceled immediately, that my payment card information be permanently removed from your systems, and that no further attempts be made to charge my card or bank account.