Bad Service Experience

The installation was done yesterday and the guys just left. I looked at the router and the LOS light is flashing red. Installers never even explained to me what is going to happen next or why there is a red flashing Not sure what that is but I am unable to use internet. I have been trying for over 4 hours to make contact with call centre and could not get through to anyone, the whatsapp line is no use I wanted 45 min and no reply. e mailed the help line and no responds.