Airtel — getting call from international number again and again

Dear sir/man
This is just to inform you that i am getting call from international number. This sim card is on my brother's name. So i got a call before some days so i received, but when i got to know that it's wrong number i disconnected that. And after that +441 +361 no, again i got from these 2 numbers. I avoided 2-3 times. Yesterday n ight i got messege in my watsapp also with number [protected]. So i tried to talk in coustomer care and inform them but i couldn't. Hoping for your response.