No way to access Abamath Ruins again?

Versalium

This is so confusing and I'm really upset right now. I had a quest that lead me to Abamath Ruins in Malabar Tor to stomp worm cult from summoning Mauloch. But there was another quest inside the ruins I couldn't pick up because my quest log was full. I thought I'll finish the Mauloch quest and then get the other one. But now that the quest is finished and I'm outside, it doesn't let me to enter the ruins again. Just...why? If I knew that this would happen, I would've cancelled one of my daily quest. Now I've missed the whole quest. I'm so disappointed. Locking the quest in this way is absolutely unnecessary and stupid.