Medlife - medlife not issuing refund

i have ordered a medicine from medlife with order id OR****KEC-***A with payment by amazon pay of ₹*** but when a delivery boy came he told the product is cash on delivery and i was shocked when i saw in the product that it was written cod of ₹***,that was different amount and by the way i have done payment by amazon pay, and i called medlife and they have not taken any action regarding this only they always tell to wait for ** hours i have waited for nearly * days but i did not receive any product after even * days i again called medlife they told to wait for another *days,they are always wasting customer time after * days delivery boy called me they are returning the product because it was cod and they are demanding payment but i declined the product because i have paid by amazon pay so why i should pay again so they returned the product but medlife is not issuing my refund. please check the issue so that medlife should refund my payment