They tried a few things on Wednesday when I had a chat with them, like signing out from all devices, removing contact emails or change the "start new conversations from" setting with no luck. The guy I was chatting with was supposed to get some more info from a senior advisor but he couldn't reach him and I was supposed to call them back, which I never did.
On Friday I couldn't send messages anymore, like always, but this time iMessage was aware something was wrong because it was telling me it couldn't send the messages.
Yesterday I saw new messages in system.log I had never seen before, but still no luck.
The messages were:
Jan 4 16:52:18 Macapsule discoveryd: WCFNameResolvesToAddr: called
Jan 4 16:52:18 Macapsule discoveryd: WCFNameResolvesToAddr: entering
Repeated a few times.
And today, I received a notification on my iDevices saying "Your Apple ID and phone number are now being used for iMessage and Facetime on a new Mac" + the computer name so I knew something had definitely been unblocked. In fact, you're supposed to receive such a notification everytime you sign in on a devices (if the previous state was signed out).
And indeed, I can send and receive iMessages from my Macbook. Facetime works again too (I could call other devices but once they accepted the call, it hang up, and I couldn't receive any call.
So, either they did something on the server or my Hackintosh session automatically expired after 4 days (I've reverted it back to a random serial/MLB/rom since then) and my Macbook is recognized again as the "master" computer behind these MLB/ROM values.
When did the blocking occur on your side?
Is changing the ROM similar to changing the MLB? I modified one number in the ROM that I injected via the VMX and will see if it happens to do anything. Apple said that there may be a serial number issue now with my MacBook Air, even though that and my VM don't share the same serial, and now they don't share the same MLB or ROM.