Overdraft payment protection added to current account

inaspin_3

I have had a letter today of my bank (Co-op) and it says 'Thank you for requesting for overdraft payment protection insurance'. I have never asked for this to be put on so i called them and had half hour on the phone with them asking why I have had this letter if I hadn't asked for it... couldn't get through to them that I didn't want it. I have never had a problem with my bank before so it's frustrated me a little bit. Every year there is a charge of £20 for my overdraft and this has just been renewed automatically, my question is are they allowed to add ppi on your overdraft when they renew it without asking you if you even want it? Haven't had anything through the post from them, or even a telephone call about it?