Hi. There are a number of factors that determine an expert's availability. It depends on when the customer might post a question. We have a number of experts in different specialties, and we don't work set hours here. Many of us have our own businesses, so we can't predict when a customer might post something in our area of expertise. We are also not employees of Just Answer. We come to the site just like you do.
I think in your case, it's more of a matter of an expert likely not wanting to tell you that even if someone values it, they don't want to have to give you the bad news that you likely cannot sell it. Even pre-ban ivory which has been "okay" to sell is now being banned virtually everywhere. Even eBay has banned all of it and most auction houses are following suit. Most online sites won't you to sell it either.
It's not illegal to own and no one should be coming after you just because you have it. I wouldn't worry about that, but because of all the new hardships, selling it is extremely hard and, honestly, getting near impossible. Because of that, it's extremely hard for any appraiser to place a value on something. Because of the bans, we have no recent sales to compare any ivory too. Not to make excuses, but most appraisers will be very hesitant to value ivory these days because we can no longer provide accurate, recent sales.
I could try to value it, but I cannot guarantee the values will be recent and would be nothing more than a ballpark and I cannot give you any places to sell it. I am very sorry to be one to say that, but I would hate for you to have unrealistic expectations.