As always, Poor service from Vox

I have a rental battery for over a year and now not lasting beyond 2 hours. I have logged the call, VOX***2, to replace the battery on 23 Nov and to date have been contacted by Vox promising it will get sorted with the last communication on 29 Nov. 8 business days later and nothing. Vox is a frustrating company to deal with and would rather cancel the rental and not have internet than have to deal with Vox. I don't want apologies from Vox, I want the contract cancelled.