Aavin has a 24-hour complaint cell handled by officials who maintain a register of complaints and ensure smooth distribution of milk. �Complaints can be registered by calling our toll-free telephone number, 1800-425-3300,� a senior Aavin official said. �Complaints are addressed by the 24-hour consumer care and support cell located at Nandanam and by our 24 zonal marketing offices,� said an Aavin official.