Medlife — rescheduled delivery date and changing of delivery address without my permission

Sir I ordered medicines through medlife on 03 sep 19 and delivery is scheduled on 05 Sep 19. On 5th sep I did not receive medicines, I called medlife coustumer care he said medicines are not available . Cancel your order and again book your order . I booked again my order . And delivery was scheduled on 6th sep .But again I didnot recieve any medicines on specific date that why I called coustumer call, they told me that only 1 medicine available and it will be delivered in banglore while my delivery was scheduled in chennai . They said again cancel your order and book again. What is this if medicine are not available why they confirm delivery . And how can they change my delivery address without my permission . Kindly