Horrible experience, bmw_rider.
As has been said previously on this thread, do get in touch with eBay personally, using the "Have us call you" option. (This is a piece of advice that I have stored as a macro because it so often seems to be the only way of getting a satisfactory resolution.)
eBay's "Have us call you" option (click onto the link) is by far the best way to get in touch with eBay. (Emails are useless, for a number of reasons, but primarily because the responses, when they are finally sent, are bot-generated.)
eBay say: We'll call you at the phone number registered to your account, or you can enter a different number.
We’re available from 8am to 10pm AET, 7 days a week.
I would also delete abusive messages once I see that communication has headed down a slope made of ordure. I know that you and your wife were very worried and upset, and that you took it seriously enough to visit the police. Or - if you want to keep the messages as evidence - I would simply not read them.
Firstly, the seller's details... Have you used the Advanced Search to find your seller's contact information? You can give that information to the police, who should be able to identify the individual and organise either a visit (from the local police) or a quick phone call advising he has no further contact with you. (However, if contact has now ceased, and there have been no further threats since the "We're all mates, we're all servicemen" message, I would let sleeping dogs lie.)
There is at least a possibilty that a reinstated negative would stir things up again. It is up to you if you want to go ahead with pursuing reinstated negative feedback (which is your right as a buyer on eBay).
In the phone call with eBay, I'd be addressing a number of things in order of importance.
- Firstly, give the rep who calls you the police incident number. Offer to fax or attach a PDF scan of a copy of the report if this is required. This establishes that you were in serious concern for your safety and that the police took it seriously enough to write an incident report.
- Secondly, refer the eBay rep to read the messages sent by the seller. Unless eBay is specifically informed by you, they wouldn't know about the plethora of threats. (eBay bots do monitor messages, but not for threats - only for things such as requests for contact information before a sale is made, or eBay addresses, or web links, or wording that suggests an off-eBay transaction.) Ask that the seller have action taken against them for having abused eBay policy in using profanities and threats. (Refer the eBay rep to the Profanity policy (and don't forget to report the seller) and the Member-to-member contact policy.)
- Thirdly, state that your negative feedback for the transaction was removed, and that you would like it to be reinstated. (This is assuming that you didn't contravene an eBay policy in the wording of the negative, and also assuming that you want the negative reinstated.)
I would not shrug off any abusive threat from anyone without taking steps to protect myself; I know we'll all read of or seen horrific examples in the media lately where threats did escalate to action. It is perhaps less likely to occur in this situation (where there's nothing personal between you and the seller; it's over an eBay transaction), but the police being made aware of the threats was, I think, a good idea. If nothing escalates, all well and good.
(For the record, if my safety and the safety of those I love were at risk, I'd let the feedback go - assuming that the threats are no longer being sent.)
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), and provides clear info into situations like this, recognising when to take threats being made seriously, when not to, how to respond (if at all), and how to de-escalate such situations. 
And there's some tools in there for dealing with difficult people, even non-threatening ones.
