Pin code and OTP emails are not received and dropped by Mailbox.org

So, I have a Standard package account for some time now. However it seems that pin code and OTP emails from well known companies are just dropped by Mailbox.org. I don't even receive them in the spam folder. So this means I can not log in to service like Bing Webmaster Tools for example or other well known services and companies that use pin code or OTP login systems.

I have PAID email accounts at Fastmail, Runbox, Posteo and free accounts at Yahoo, Tutamail and a rarely used Gmail(for obvious reasons). HOWEVER all of these email services receive pin code and OTP emails WITHOUT ANY problem and they do NOT end up in the spam folder. That should be a clear description of the situation.

I have already opened a support ticket but have not heard anything since 11 May......
This problem and the lack of response is making Mailbox.org practically useless?! At least with the other paid email service, even though I rarely need it, they respond very quickly.