No, I haven't, and according to what paid2 posted above I don't think that is going to help either.
Please don't panic (at least it looks that way.. I think it's only harmful).
I think if eXch is silent, there are reasons for it (and as far as I know, not a single request over the past years has gone unanswered... all cases have been resolved). Moreover, if you remember... I once suspended a campaign for several days because I did not receive a response from eXch for a long time, but despite the silence, their service works automatically, and their reputation is impeccable.
I also do not doubt the exch service, I believe that there are some justified reasons why they are not responsive in this case. However, a month is probably too long a period to solve the problem. I hope that the delay will not cause NotATether too many problems.