Tata AIA Life — Life Insurance policy pay out not received

I have taken out a Life Insurance policy with Tata Aia that pays out every 3 years. I didn't receive the cheque for 2016. I raised a complain with Tata Aia. They checked and confirmed that the cheque was not cleared in 2016. They promised to credit the amount to my bank account in 3 days. How after 1 month they are now saying the cheque was cleared in 2016! I can't believe they can do this to a customer!