Bad Fibre internet service provider

Upgraded to a 500MBps download line a year ago. Three months ago found out I'm not getting the speed I paid for every month. After multiple technician visits and calls for assistance. I was told the router does not give the speed I am paying for. Still after that revelation no attempt was made to provide an adequate router. This was just left at that. I indicated my intention of canceling but this didn't phase them. Now they failed to release the fibre line for my new service provider even after the required 1 calendar month notice have come and they ended my service.