Hi SirI cancelled my du home internet connection...

Hi SirI cancelled my du home internet connection on August 25th and all devices send back on Ajman city centre branch(I applied fibre optic cable connection but they gave me sim internet connection because my home area there is no fibre optic cable, more over sim card connection not working properly. poor internet quality. That's why I cancelled)After then they send bills every month. I called every months they waived bill amount. But now told I should pay November bill compulsory. I called them why I pay bill because of connection is cancelled.