When I reached 30th level, I received a mail from my class trainer Oggur in Bree Town. I detached an item (a letter) and started the quest "Another Matter of Importance" by right-clicking it. Then, I don't know why I did that but I abandoned quest. I was hoping that the letter (the detached item) will stay in my inventory but it vanished. Is there a way to restore that item or mail? It looked like a important quest and i would like to do it. Thanks.
The quest IS important. It is the 30th level guardian class quest - but the letter quest that sends you to him is irrelevant. Just a 'heads-up' that it is worth talking to a trainer at that particular level. Don't worry about it. In fact , just talk to ANY guardian trainer to pick up the l30 class quest, now you qualify. Since it is set in Trestlebridge, you will most likely want to be near Bree anyway, tho.