Fraud call selling the samsung mobile on discount

I received a call on my mobile saying that she was speaking from samsung head office delhi, n i am selecetd for a samsung galaxy A5 new mobile on dicounted price of 4250 (base prise 18999). the parsel was send to me by speed post and advice to pay cash on delivery to post office. as i received a call from post office, i collected it after paying COD amount rs 4250, but after opening the pack it containts vallet hardly costing rs 50. i called back her regarding the same, n she ask me to send the whatsup images and said that she will check the amount was received by her or not , after that she said that it was by mistake and i will received the new mobile at my home by local samsung servise centre till evening. i have recorded all her talk with me in my phone. i also here the voice in background when i was talking to her about the same to other customet that their no was selected for samsung mobile offer. and they will sebd it to them by post. now what to do, to stop theswe racket these person from cheating the other?