Metrofibre unwillingness to help a paying customer.

So I have MetroFibre, I didn't have an issue with the service or the company, but then it started. The terrible internet connection. It's so bad that I have to keep any device near the router or in the same room as where the router is. I have been told it's the voltage in the house, the user name are incorrect, the devices are now not compatible with their network, to many devices are on the same network, I am using the wrong password. Once I move 3 metres from the router I get disconnected, then I must put the device next to the router to stay connected. I am still waiting for them to send a technician out to test the router or to replace the router.