Getting the same issue, seems like it's a localised issue in some places not a wide spread issue, maybe on exchange side. Getting the same replies from them.Called them up for slow service. They are denying there's any backend issue. The support guy had NO idea if there was an issue. According to him, it was an issue locally at my house. With both connections (yes, we have two PTCL connections) !!!!
Definitely looks like over subscription to me