India Post — complaint about product retained by custom

Sir, I have ordered a product from ali express and it comes to India and now stuck up in mumbai custum. Early it shows "Retention Reason : Retained by customs for unspecified reason" in tracking status of India post but after 3-4 days it shows "RETAINED BY BORDER AGENCY/SECU" in tracking status of India post. They have not contacted me till now either by mail or by call. I don't have any clue what to do. Please help me by providing information as same product came in India earlier to customers without any such problem of custom. My order no is "RY[protected]CN"