My fault apparently
Had issues all morning with our IP Phones, so inevitably it's my fault that they don't work. As soon as I mention what's happened it's "call BT now and find out when it'll be fixed, we can't work without phones". Except it's not actually a BT issue and we aren't a BT customer? Now if only I could have changed jobs 2 weeks earlier... (still here for another 2 weeks)