The Co-Op and server-related problems will be resolved in the long run. Our team will move the game's backend onto a new provider later this year and we expect a more stable connection without any similar issues you all ran into. This will take time but we are already working on the migration.

We also compensated all 4 of you as well: your main chars have some decent lootboxes in their inventories. Kindly mind, the loot-loss problem appears if at least 3 players play together. Playing with only one player reportedly seems fine.