Invoiced for router 4 months after contact was terminated

My name is Munier was a customer for 3 years left Home Connect due issues that could not be resolved I had a router that I thought was paid for after I left just to find a invoice that was sent to pay R900 for a router that does not working anymore made arrangements for router to be collected but it was never collected just to get another invoice about a R900 outstanding Please read your find print when signing with Home Connect I am going to pay the invoice before I get blacklisted over R900