Medlife — Refund is getting delayed

I placed an order with medlife on 1st of March 2021. My order I'd is ML-OR2773BLC-003A[protected]. I payed full amount of Rs.1072.82 for the order. My order got confirmed on 1st March. Later on 3rd of March before dispatch they informed one of the medicine (Droxyl clav 500/125) is out of stock. They refunded the amount Rs.575.40 for the unavailable medicine. On 5th of March, they came for delivering the remaining available medicine and asked me to pay the money. As I have payed the amount already, I refused to pay again and get the order. Till today I didn't get the remaining amount refund. I am following up with them through customer care and they say it will refunded in 24 hours and it is delayed because of technical issues. Every executives says the same answer. Please help me to get the refund back