Hi MaryK
Welcome. We don't usually take ads in the first post. Better to post in "What kind of Pearls do I have?"(and how much are they worth) and state you will list them on eBay.
Did you check the completed listings for 22" Mikimoto? The highest priced one sold in the last 90 days was $1,200 in the section for 22"mikis.
However none had the box. It sounds like you have the paperwork. You need to make that clear in your ad, because it enhances the value to have a bill of sale or Miki Certificate (if they give them out). Even a photo of the certificate or bill of sale or whatever will take your necklace way out of the realm of the other mikis. However, the moment you walked out of the store, they lost about 75% of their value if you sell them to a reseller, if you could find one. You would probably get 30% of their original sale price at an auction house after fees.
The only way you get even near the price you want, is for a person to buy them from you on Ebay as a gift or for personal wear. The paperwork will make your authenticity stand out, so you may be able to get a couple of grand, even $2,500. The only thing that makes it more valuable is the brand name. Otherwise that strand would go for less.
Here is a sold listing for the best price on eBay. $1,789.00- but if you read the listing the seller took a lower offer. This was listed under pearl necklaces "22", so I just found it. That makes the $2500 price likely to sell.
Go ahead and keep your starting price, but add photos of the paper work. The new appraisals have to be for
resale price, not insurance price. Retail is about 25% of an insurance appraisal.