The ticket I received from Blizzard 
Your ticket has received the following response:
Hey there,
I'm Specialist Game Master Kaltheramis and I just received your ticket about missing progress in D2:R.
I entirely understand the frustration of spending time to progress in the game, only for that progress to be lost and, if you have not already done so, please report your experience on the forums as a bug [https://battle.net/support/en/article/15043]. This will not restore any lost progress, but will help our developers and engineers address the underlying cause to prevent it moving forward, and help out community managers by getting an idea of size and scope of the situation.
For D2 and D2:R, character and item restorations do not exist. This is not a policy, but a technical limitation. There exists no tool that would allow Customer Support to recover, or restore, or create, or remove items or characters within D2:R.
I understand that this may not be the answer you were hoping for, but I am glad to explain our scope of support on this. Have a great day, and, of course, if you need other assistance, don't hesitate to reach back out to us.