*****ing my fibre line

We changed fibre ISP to Vodacom. They came to our house with a router they could not set up. They said that they would be back tomorrow to set up the router! Well tomorrow never came. We then contacted them and cancelled as we have been without fibre for in excess of a month. BUT NO, they cannot cancel because we owe them R1500 for the installation!!!! What installation??????? Now they have taken our fibre line and will not release it so that we can get a new ISP!!!! What a bunch of ******. I WANT my fibre line back so that I can have internet, I WORK FROM HOME FOR GODS SAKE!!!!!!!