Alexis was correct that it should be 'called', either way. 'A few days earlier' is a relative time phrase. It relates to some defined time that would have been mentioned earlier. 'A few days earlier' means 'a few days before that time'. 'A few days ago' means 'a few days before now'.
e.g. It was my birthday last month. I had had a cold a few days earlier, so I wasn't feeling well at the time.
'a few days earlier' is a few days before my birthday, i.e. last month some time, not a few days before now.