Sorry to interrupt you both fellas, since your reply is a bit off-topic, bitblender signature campaign is a way too different from the case of OP.
Your only way is to reach out their support page, you can contact the official account of bitblender which his profile link is mentioned above, the account seems inactive since first week of the month though.
I don't think lutpin can help either (if ever) his way too busy in personal life at this moment that he can't managed his personal life and his work here I guess.
I don't find this very off-topic considering he is usually pretty active in managing his signature campaigns and such on the forums, and the sign that he's not active on them means there's likely something happening in his personal life as you mentioned. I occasionally find contacting the campaign manager of a project can help resolve a problem, since such people are usually close to admins that can help out with issues on a site, such as what this member has.
The best method of communication is going to be their support page, though I have no idea what the response time on the site is. I have never needed to use the support on their site after mixing coins.