We had some issues with them, involving emails not being delivered to us, and IPN not working also.
What we did was plain simple, we called support, we explained the situation, they've told us
that it could take up to 7 days for them to respond to the support ticket
but not many additional information was given.
I must say that they've fixed the situation and all started to worked, like it use to,
in about 3 days after the call (but without any notification from their side, just old notification
emails started to get delivered, and the IPN did too).
Good luck !