Life Insurance Corporation of India [LIC] — lic premium paid twice, but didn't get the refund

My lic premium is paid twice, the second premium was paid on 25th sept 2018, i have made complain to there customer care several time but problem is not solved yet. I also made complain to the concern branch, but its already a month passed, but didn't got the refund. Lic demands that they have refunded the amount to my account on 4th october 2018, but my bank transaction doesn't reflect that. I also informed them about that too, but still not refunded. Please help.