Strong service, horrible cancellation & billing department

What started with a great service provider for internet has now soured upon trying to cancel my service. I sent cancelation instruction in May and my last day of service is meant to be the 30th of June as i've moved houses.

Now a month later after my service is meant to be ended, i'm getting invoices for July billing plus you can never seem to get any repsonse from their collections team regarding paying for the router! I told them from the start and responded to all of the mails saying i'm happy to keep it, please send me the bill to settle. But then weeks go by and then someone eventually contacts me saying, 'oh, we need to collect the router still, when can we come fetch it...'

Come on guys, to drop the ball at the end of what was a great experience is highly dissapointing. It cannot be this hard to settle an account which i have to keep chasing you to do! Please rectify this ASAP.