If I understood correctly, you sent TL an email because, after receiving a glimmertrove from a Hunting roar bandits adventures, you lost it due to a sync glitch (the game autoreloads and you lose whatever you had done for the last seconds), right?
If this is the case, then the answer TL gave you is completely normal. We must try to avoid sync glitches by force closing the game at night and refrain from playing with a bad internet connection, because TL will not return whatever we have lost from one of those glitches.
Everyone else here had sent an email because, while doing the glimmertrove quest (the one where you craft supperyummy pies and send your knights off to get that trove), their game autocompleted the quest without allowing them to send their knights out to get the trove.
And to answer your final question, of course you are allowed to have more than one trove. You can buy them from the market or get them from an adventure (and hope there is not a sync glitch while collecting it)