I called back number (02) 9842 4777 spoke to a woman who said company name is Bosch Security Systems .

Woman, who sounded asian, called asking for 'Joe'. Told her it was a wrong number and hung up. 5 minutes later, she rang again - this time asking for 'Lu-anne' and wondering if i called them regarding tech support. Also called me with another phone number after I blocked this one [(02) 9824 4791]. Very fishy.