Is nominee liable to pay any loss to Insurance company

My Uncle who passed away recently had kept huge amount in Life Insurance policy under "Jeevan Shanthi" & "Jeevan Akshay" with option "A" & mentioned my name as Nominee. When I submitted my claim to LIC office to receive the benefits, to my surprise, I got a notice from LIC to pay back Rs 1.5 lakhs as they have paid Annuities for few months after the death of Annuitant. Now, my doubts are as follows, 1. Is Nominee liable to pay the annuity amount paid to the Annuitant account after death of Annuitant. 2. In LIC, in respect of above mentioned policies what is role of "Nominee". 3. For example if a person has taken the above policy what is the maximum amount he/she can invest in this schemes. Is it based on annual income? Consider one case say policy date is 31.08.2018 purchase price amount RS 50 lacs, option "A" & Annuities can be paid on Monthly/Qly/HY/Yearly basis. Imagine that policy holder dies on 30.08.3019. What about if he has opted monthly Annuity a) last monthly Annuity paid is 31.07.2019. Is Annuitant eligible for 30 days Annuity or Nominee is eligible? b) last Qly Annuity paid is 31.05.2019. Is Annuitant eligible for annuity from 01.06.2019 to 30.08.2019 or Nominee is eligible? c) Last half yearly Annuity is paid on 01.03.2019. Is Annuitant eligible for Annuity from 01.03.2019 to 30.08.2019 or Nominee is eligible for this amount. d) Since Annuitant died on 30.08.2019 is Annuitant eligible for Annuity from 31.08.2018 to 30.08.2019 or Nominee is eligible for this annuity. What they have informed is, Nominee will not get any thing & instead nominee has to pay it back to Insurance company if any amount is paid to Annuitant on or after the death of Annuitant. When I wanted to know where it is mentioned in policy & where is the consent from nominee they couldn't provide the details & only showed one line in some other policy that "annuity payment day Annuitant should be alive". In addition to to above doubts, please provide me information on how Insurance company will consider payment of annuity which is due on date of death ex: policy date 31.08.2018 Policy amount 10 Lac under "A" option Yearly Annuity say Rs 2 lacs. Date of death 31.08.2019 time 11.58 a m. How much Annuitant/Nominee will get on submission of claim form. Let us imagine that Insurance company has paid Annuitant Rs 2 lac on 31.08.2019 as they are not aware of death of Annuitant. Later they will come to know say after one month (30.09.2019) when the nominee submits claim form for claim settlement. Please provide me information on how the claim will be settled & role of Nominee & benefits for nominee in this case.