Air India — Not get the refund

Address:

45 sahyog society, khunh,chikhli dist navsari , Gujarat 396521

I had booked air india tickits containing booking reference no zdvhz, hwh69, jqnmg, yvoo4. All are doestics travels between 10th may to 17 the may, 2020. Due to covid-19 all the flights are cancelled. From last 1 month i am trying to get refund of such booking, but still i have not got it.