Caller Display Stopped Working 1st March

Just randomly stopped working, no rhyme or reason behind it. Of course, talking to someone in their outsourced customer service told me that it was my handset that didn't support it, despite it being the handset that's worked just fine with their caller ID service for the past 8 years. I just raised a complaint with them because it's easier than arguing with someone, hopefully it'll get raised up the support queue to someone that knows how to turn it back on.