Vodacom Shocking service!!

I've tried a whole day to talk to the cancellations to cancel an expired topup router but the moment they hear the word "cancel", dead silence and either get cut off AND then the "review call" comes through to give a Review of their call.

The shops won't help me ... since I can only do it by phoning *** !!!! What on earth can I DO!!! Stop paying !! Maybe that will wake them up!!