Undisclosed charges on contract renewal

I very recently renewed my contract via your call centre. I don’t know why I am surprised that you tried to sneak in “Contract Cover Plus” without it ever having been mentioned by the person I spoke to on the phone, or part of our previous agreement. There has been surprises during my last 3 renewals that took hours of my time to resolve. I have cancelled this forced add-on immediately as I became aware, yet I have been billed for it. How is this not *******? Don’t call me, just fix it!