Update: Update is that there is no update, because they just don't respond anything. This case is marked as unresolved on AskGamblers as well already.
It was expected to happen. Because Thunderpick doesn't cooperate with the 3rd party mediators, their strategy is different. They want to solve the disputes internally, which will always remain questionable. Haven't you received any response from their DRO team after sending an email? They usually give
a response after 7 - 10 business days by doing investigation.