In the most recent case, it's difficult to tell one way or the other. I'm pretty sure some of them have been native English speakers, though.

(Yes, I've often noticed that many of the least comprehensible support emails I get come from native English speakers, whereas non-native ones tend to take great pains to be clear even if non-idiomatic. There are occasional exceptions – most often from East Asia, where I suspect the local grammar tends to differ rather more fundamentally from English than it does in most European languages – but by and large the people who go out of their way to apologise for their poor English are not the ones who really should be doing so.)