Complaint regarding refund due from Air India

I have booked two tickets in the month of sept 2020 for my parents (journey date oct 5th from hyderabad to delhi, delhi to toronto) but cancelled the tickets before 24hrs because mom tested covid positive. I have been calling air india since october for my refund but their response is pathetic. I have even dropped N no of emails but still no response. I have been calling these guys every alternative day and they say same answere that i will receive my money within 7 days but havent received till now. The refund department will never be commected via phone its the customer servise guys who answers the calls and those people dont have access to any information a part of saying that i will receive my refund in 7 days. It has been more than 5 months iam waiting for my refund