Appalling Vodacom Service

It seems Vodacom are unable to cancel a contract. I placed an online order for an upgrade and requested it be cancelled the day the device arrived. It was collected by RAM and arrived back at Vodacom 3 weeks ago tomorrow. I have lost count of the times I've called Vodacom to follow up on the cancellation and have been told numerous times that the matter has been "escalated". To where they escalate it I have no I idea as there is absolutely no response from the idiots tasked with cancelling this contract. I've mailed Tracy at *** a few times and finally received a one line response with a service request ticket that I can't open. I have been phoning almost daily to follow up and still no further progress and nobody is able to access any useful information regarding progress. All I get is "We can see that it hasn't been cancelled yet" which is the reason I'm phoning. Nobody at the call centre has any idea what to do, all they can do is email *** where nothing happens. Unable to give contact details of anyone that might be able to help so that I can follow up myself. All this despite being billed for the device that I sent back weeks ago. The cancellation was done well within the cooling off period. I've been a Vodacom customer for almost 20 years but not for much longer.