Airtel — Higher charges

See i took 399 postpaid plan from airel 2018. Till june 2020 i didnt face any problem but in july 17 to august 16 2020 bill they charged Rs.333 for an international sms charges. I didnt even sent any international sms. But they are saying i have sent and you have to pay it. so i asked them proof with content whatever i sent. For that they said no we dont have that, but If you want we will give the number, date and time. Are they mad? Its already there in ebill. They are cheating people and simply charging high. Airtel is fake. I want the resolution for this. Please help me with this