Not exactly the answer I was looking for but I'll take it for now. I can guess a month. I can also guess this system may be somewhat automated and another members experience might give me insight as to when to look in the mailbox (I can go weeks without looking) and I havent accepted a registered letter in over 15 years. Maybe I should contact them and ask them where we stand now and when to expect a follow up.
Unfortunately, there is no real time table for these things. But if they wait too long, that can hurt them. If you hear nothing for 2 years, then they come after you, you say, "they knew about me owning the domain, they did nothing, that would be express permisoin to use it".
Yes, they can come after you at anytime. But on the contrary, if they knew about you, contacted you, then did nothing for a couple years, an arguement can be made they gave implied permission. This defense has been used in UDRPs before and has been effective. There are others factors that ae involved, but this can be an effective one.
Can I use trademarked names or products in my book?
A trademark is a word or symbol that identifies a product or service of the trademark owner and is used to distinguish it from the products or services of others. A trademark prevents use of a product name, slogan, or symbol by a competitor and also protects against damage to public goodwill associated with a specific product or service. It is permissible for a fictional character to drink a Coke or read Sports Illustrated. Your legal risk would be increased, however, if your use could potentially injure public perception of a trademarked name or product or cause confusion as to the ownership of a trademark. Also, you are at risk if you use a trademark as part of the title or subtitle of your book.
Domains have little protection for fair-use. Get a lawyer if you really want to keep this. You will need some sound advice and a good defense. You would most likely lose in a WIPO decision rather quickly. Then you will need to go to US Court system to overrule the decision...and there you will need to convince a court you have legitimate rights over Ebay for the domain. Good luck on all that.
I can't overstate how bad of an idea it is to mess around with a company of this size. Like it or not, eBay has lawyers on retainer just itching to "go to work" on you or anyone else that steps on their trademark.