As per your statement, it seems your employer has tie up with LIC under Group Gratuity scheme. That is what they have told you that they are awaiting cheque from LIC which you have mistook they are asking LIC policy from you.
If they have really had tie up with LIC under Group Gratuity scheme and have paid premium regularly they should have cleared your Gratuity quick.
Now that as it is nearing one year, better you take the matter legally with the Assistant commissioner of Labour of your region. Attach all the copies of email correspondence as a proof. Your employer cannot evade further.
May be your company having the gratuity account with LIC, so may they getting delay from LIC to get credit amount in their trust account, in my opinion wait for some time for the claim.
No need that you should have a policy to claim the gratuity, once the amount approved by LIC then your company will pay you amount by cheque.
If you are thinking that management is deliberately doing this with everyone, then come forward and teach them a lesson for the welfare of others.
As per Rashmi, she got relieved on 9.7.2018. It is almost nearing one year. LIC will not take this much time, provided if they have cleared premium up to date. Most probably employer might have recd the amount from LIC to their account and failed to disburse it or doesn't want to settle.