General Knoxx Vault Mission Bugged

So i did the vault glitch in the mission “its like christmas” and it get bugged because it get the second point of the mission checked. I want to do all the missions in the dlc for an achievement but now its bugged. I tried to use Willowtree but when i delete or change anything about the mission the game delete all my items and guns (not modded)

Realistically, the best way would be to find someone who has the mission open and doesn’t mind completing it, then run through with them. It would need to be on the same play-through. You could try posting in the relevant on-line play section (or just post your platform here)