Airtel — Cross call connection

Address:

pune , pimpari chinchvad

From last 2 days I am experiencing Cross Connection when attempting to make a call, What happens is when I try to call someone for example my father, he receives the ring, when he picks it up, he doesn't hears my voice but the call remains connected and on my side, instead of hearing his voice, I hear conversation of someone else on another call but they don't hear my voice.