Your serial numbers do not change when you reset activations. Instead, when you reset your activations, that serial number opens up again to be activated on two machines. Any machines that were previously activated using that serial number, will need to be activated again.
From what i can tell the activation service is working normally. Someone from Tech Support should be able to give you some more advice soon, but I'd recommend you check your firewall to see if it could be blocking access to the activation server.