PharmEasy — wrong medicine delivered to me

I ordered for a medicine few days back in pharmeasy app from chennai, tamilnadu. I ordered for 3 strips of a medicine. 2 strips i received were as per my request. But the third strip was incorrect. A wrong medicine was delivered to me. I called the call centre and spoke to karanjeet associate and sangeetha floor manager. I explained them the scenario and also told them that until i received the courier and opened it, i didnt know that the wrong product is given. They agreed that and also agreed that the mistake was theirs but just said they can not take the complaint. It was such an irresposible reply. How a person can take a wrong medicine?