No contact number for Open Serve

My concern is that Open Serve does not advertise a contact number in order to contact them. I had 3 guys, plus a superintendent arrive at our premises, wanting to install. No prior notification was given beforehand. How do we know it is legit and in order ???? we managed to get the superintendents name and his cellphone number. I would have preferred being able to contact an office. Could someone from Open Serve please give me a call in order to confirm the workmanship. I see a lot of bad reviews to which Open Serve has also not rep**** !!!!?????