Fibre Installation-not happening on time as promised - SO***

We ordered Fibre through Vodacom on the 1st of Dec and were promised 21 working days for installation. Vumatel has installed the line and the router today-21 Dec ie within the 21 days . Now we are told the scheduling department is closed for Christmas and we are waiting for the Vodacom hardware installation of their router, we are now extremely concerned we are not going to have our Fibre active when our current service provider stops (31 Dec). We are a small business and need the fibre to be active and working as from the 1st of Jan 2018 otherwise we cannot conduct business!!