Legal Question in Administrative Law in California

First try to determine if anyone on those lists has been contacted by the new club or not. A few people must have bought items with their credit cards and maybe you can get their contact information from those vendors and then check if the new club has contacted them. Then write them a sharply worded letter [it will be stronger if it comes from an attorney since that implies a lawsuit] with the facts and your reasons for suspecting the list may still exist and your being willing to hire an expert to see if the disk information can be recovered. based upon you r knowledge of the other people you have to decide whether you are gentle or very aggressive. Point out some members of your club want to sue for conversion and get an injunction to prevent use of the missing list but you are trying to arbitrate this so as to not create a lawsuit and hostility. You do need to have some evidence if you are going to try to force them to give over the missing information. You also need to find out from your other club members if any of them have access to any parts of the missing lists.

Good luck.

[not proof read]