Airindia - Flight ticket refund

My In laws flight tickets were cancelled due to covid back in march ****. there were * flight tickets that were booked. After that we rescheduled the tickets for travel again in april **** but unfortunately my father in law could not travel and we cancelled the ticket requesting the refund. I was initially told, i will be getting the full refund and later i was told i will be refunded remaining balance after cancellation charges. but did not receive any money till date. I have followed up multiple times. Opened multiple case with airindia requesting refund. When i call customer care, i only get one answer, give us * weeks our back end team is looking into and eventually the case falls of. i ended up openeing new tickets multiple times as result of either change of process from airindia or because they claim that the case is nolonger valid etc.
below are the case numebrs from the past

Case # ******** - Most recent - opened OCt *, ****
old case numebers

Case ID- ********
Case ID- ********
Case ID- ********
Case ID-********
Ref-WB-IHYD*********
Ref-WB-IHYD**********
WB-IHYD*********
WB-IHYD**********
WB-IHYD**********