I once got neutral feedback for late posting.
I'd emailed the buyer to explain that due to the massive amounts of ice (it was snowing, freezing over, snowing - the ice was inches thick) I wasn't able to get to the post office that day. I emailed her again the next day to say her parcel had been posted. That day was the 2nd day since she'd paid, and she'd paid after the post office was shut, so the posting had been delayed 1 whole day.
OP, as long as you get your parcel by the estimated date, I'd say the seller is fine in that respect (assuming she isn't in an area with 6ft snow drifts - if she is, give her some slack). Not responding to your emails though, I'd mark her down on the individual rating for that.