Turkcell Charged Me for International Calls I Did Not Make

On behalf of my son, we purchased a postpaid line from a Turkcell store using the social support discount. We have been regularly paying a monthly bill of ₺337. My son is illiterate; he can only answer incoming calls and uses photos to make calls. However, the May bill came out to ₺207,067 without any explanation, dated May 25. My son does not know how to make international calls, yet while he was asleep, international calls were somehow made from his phone, each charged at over ₺1,000 per minute. We are in a very difficult situation right now. We kindly request that the Turkcell store correct this mistake. We have always paid our ₺337 monthly bills on time, and we expect this matter to be resolved promptly.