Vodafone — Vodafone PostPaid - VI Kolkata - Security deposit not refunded after MNP

I was a VI postpaid customer. I have opted for MNP from VI to a different Network. I had security deposit with VI. At the time of MNP, I was informed that I will get the full refund for the security deposit within 45-60 days from MNP. Its been 70 days since the MNP was done.
I was told that the cheque will reach me within 45 to 60 days. However, no cheque has come.
After contacting the customer care, they told me that cheque is issued and dispatched. But it will take another 45 days to reach me. Also, no tracking ID was provided to track where the cheque is.. I think they dont want to refund the amount and want me to get frustrated and stop following up so that they can embezzle the entire amount.