Failed to activate modem

Technicians from Telkom came to our home on Saturday 12 March 2016 (without calling to ask if it's appropriate or if we want new devices installed) to install a new fibre optic ADSL modem. After putting in new cables and setting up the modem, they ensured us that the transfer from the old to the new modem would be completed by Monday 14 March 2016. Instead, the new modem did not activate, and the old modem also didn't work anymore. By Tuesday 15 March 2016, the old modem worked again (but only with the desktop connected to the modem by cable - no wireless devices could connect to the internet through WiFi. After spending hours holding on for a solution with the call centre, the new modem is still not working and the old one cannot connect to wireless devices. We don't appreciate goods being forced upon us and then not being serviced afterward.