Turk Telekom Unexpected High Charges Complaint

I am a Turk Telekom customer, and I rarely use my SIM card while abroad to receive SMS messages. Besides that, I have not made any calls or used the internet. However, last month, despite only having a brief conversation with my bank for about 15 minutes, I received a bill of over ₺700, which has now skyrocketed to ₺1,359. I cannot view my billing details in the app.
I urgently request an explanation for why my bill is so high. I need clarity on this matter as it is unacceptable.