If it got abandoned, there is probably a quest giver out there standing around waiting for you to wander by. The trick is finding them. Fortunately, the game has a different icon for the NPC and doors when it involves the main quest. If you can separate the Southern Elsweyr ones from any other main quests you might have going, you can probably follow the markers to the quest.

Edit: If you remember where you left off, you can always pop over to UESP and go through the quests listed there, find the quest giver and where they are supposed to be, and go there to see if that is the quest you need.