Unexpected PUBG Mobile Bill Shock

I was shocked by a scary thing that happened to me with Türk Telekom. Under the guise of the "PUBG Mobile" app, I got a big bill that I didn't know about. My bill, which is usually 150 TL, jumped to a shocking 700 TL all of a sudden. Even worse, I'm not even a member of any gaming site right now, but purchases were made using my number. When I called customer service, they told me that my number could be used to make purchases even without a subscription. I don't understand why these charges showed up on my bill even though I never got an activation code.