Act 2 Cruel Bugged - Can't Progress

I had the two medallion pieces for the Ancient Vows, but they disappeared from my inventory. I'm at the part where I need to insert the medallion pieces in the valley of titans, but I no longer have them. I have tried farming in Keth and The Bone Pits, but they have not dropped after a few hours.

Additionally, I have The Horn of the Vastiri for "The Trail of Corruption" quest, and am told to 'Use the Desert Map to return to the Sandstorm'. I've done that, but I cannot get off the Caravan, there is no door/portal opening up for me to exit. I tried going through all of the Halani Gates to get back to the Sandstorm, but when I arrived I'm unable to interact with the horn or Asala.

I'm unable to progress further in the campaign at this point, so this is a bit frustrating.

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Additionally, I have The Horn of the Vastiri for "The Trail of Corruption" quest, and am told to 'Use the Desert Map to return to the Sandstorm'. I've done that, but I cannot get off the Caravan, there is no door/portal opening up for me to exit. I tried going through all of the Halani Gates to get back to the Sandstorm, but when I arrived I'm unable to interact with the horn or Asala.

You don't need to get off the caravan. Use the desert map to move to the sandstorm then walk to the front of the caravan, you will seen an interaction spot there.