Blocked router- worst service provider ever

Supersonic has yet again disappointed on their services. After their agent messed up my contact details, struggling to get hold of them to get statements, yet every day the invoices are being populated. I have cancelled this services as there is no light at the end of the tunnel. And now they have gone as far as blockier my router which was not provided by them, I am not able to set up my new sp on the router. During the activation process, the consultant that came to connect me logged into the portal and changed the Wi-Fi name and password, however I was not provided the details to log into the portal should I have needed to change my Wi-Fi password or secure my router a bit better. Now the router is blocked from accepting new service providers of which I am at a inconvenience again coz I have no Wi-Fi at home and I have to pay for a router again which they did not even provide to me