I don't think I have ever left a neutral and only one negative (item was smaller than measurements in listing and a fake,seller was naru'ed not long after) in 12 years. As I posted above, I would be leaving a neutral fb at least.

A neutral has the same weight as a negative now, as far as seller defects are concerned. I suppose a neg is more noticeable with the red dot, but that is about the only difference.

There isn't any excuse for this sellers delays  and non communication. Bit unlikely he was unable to send a message to the buyer for over 7 days. The seller gets the buyers personal email address as well, so the ebay msg system possibly playing up doesn't wash for an excuse for no communication.

The OP asked for opinions (general consensus). up to them now, after reading responses, what action they will take.