Just had a call from 'O2' offering me 40% off my next bill. It was clearly a scam and had I continued they would have sent the security code to my phone and asked me for it. (The one that says don't ever give this to anyone, including us!).
I told them they we're scamming me and they argued back. "How can you say that I'm scamming you, what evidence do you have".
I'm just in shock at how brazen it was - if you are trying to scam some one and get called out, why would you continue the conversation?