I know this is a years old post, but I just had a call from this same number. I ignored it as I didn't know who it was, but they've left a voicemail to say they're just checking to make sure a fault I had with my broadband was resolved. Seems legit as I did have a fault that was fixed last week and they advised that if everything is alright, I don't need to contact them and the case will close on it's own on their side if they don't hear back from me.
