Southern Railway — refund for cancelled train

I had booked four tickets from kollam junction to tambaram on 18/08/2018 train no. 06028 and my pnr no.[protected] the train was been cancelled due to the kerala flood and landsliding. I got message and i confirmed by enquiring in the station they informed that the full refund will be initiated after 4 working days. I have not received the refund yet please do the needful as early as possible