Vodacom Fibre doesn't know what FREE installation means

End of July 2018 I had fibre installed by Vodacom on a 12-month contract with free installation and free (lent) router. The contract then ends Aug 2019, but they with no instruction or mention switch to a month-to-month, which was fine. Now I decided to move to uncapped on a different ISP. On March 24th I call them and ask the account be cancelled because I want to move to a different provider. They say one calendar month and then it can be stopped. Now the new ISP I'm moving to askes if I can ask them to release the line a few days early so that they can come to install the new router. I contact Vodacom on the 17th and do the request, they say there may be a quote before they will do it because there may be outstanding costs. I agree since I'm on month-to-month and are all paid up. After two more phone calls, I now understand that Vodacom has my line hostage and refuses to release it because they paid for the line to be installed and I have to pay them back. FREE ... Vodacom ... FREE, do you understand what that word means? I'm not in contract with you and yet you hold my line hostage and say it belongs to you and even Vumatel (who physically own the line) can't do anything about it. How the hell does that work? I looked over the FAQ's they sent on installation, no help. I understand if I cancelled during the 12-month contract but to come back 8 months after a contract ends and force me to pay them back for the FREE installation. This is beyond frustrating since I work from home and the whole COVID-19 situation compounding this. I'm deeply disappointed at this hidden cost behaviour they are riding their customers on. After 3 calls I still don't even know how much they expect me to cough up for the FREE service they offered.