The problem should be solved for now. It will take some minutes before all data will be received again. So it is possible that some devices are up again and some are still down.
Unfortunately this is only a workaround and we are still looking for a structural solution. I will keep you updated about this.
I think a structural solution is to move away from a message broker at the T-Mobile side. It does not add any value for integrators over an (open) APN, and creates maintenance for T-Mobile. Apparently the network is still functioning, and has excellent coverage i must say so that is not the problem.