GATVOL!!!Serious internal communication issues!!!

I took out a month to month fibre agreement from Vox in July 2017. The package we took included a handset. After a month, we found the internet to be slow, so we upgraded to a faster package, which didn't include a handset. Although we were now paying more, the handset had to be returned, as it wasn't part of the package we upgraded to. We were told that a courier would pick it up from us....no problem. +-3 months later, I get invoiced for 'non-return' of hardware. A few emails and phone calls later , over the duration of about a week or two, the invoice gets credited and a courier arrives, unannounced, at my house to pick up the handset. I was relieved, thinking that this issue was over. 12 Months later, we had to move to a new house and the area we were moving too, had no fibre connectivity, so we had to cancel the contract. The cancellation process itself went by hassle free, until it came to the collection of the 'hardware'. About 2 months after we had moved to the new house, we were told that a courier would be picking up the hardware, my wife waited for half the day but no one arrived. Eventually I get invoiced again for 'non-return' of hardware. More emails and complaints, and a few weeks later, the courier collects the hardware, with NO HANDSET (because it was returned last year), only to get invoiced again for not returning the handset. Today, I have received another invoice, with interest, for not returning the handset. I owe VOX nothing, I have no business with VOX, so please stop harassing me. Just in case you are not sure what to do....go and check your records! ACC ********** .