EMERGENCY Arbiter of ash

Dear Grinding Gear Games

I'm currently together with my brother on the final boss Arbiter of ash and we just died for the first time. A message appears saying I have 5 more attempts.

Well, I can no longer enter the portal!!!!!
It is NOT possible! What is going on?

I went back to the monolith and ALL my stone fragments are GONE!
I've invested weeks to get this far WEEKS! Now I have to start again from zero?

I expect a solution as soon as possible and a refund of the 3 stone fragments.

Kind regards

P.s I posted the text also in Steam and wrote you an e-mail so you can also deliver the solution there if you like.