In the last two weeks, I have received at least 5 calls from numbers beginning with "613-111-20##" (the last two digits are always different). One of them was 613-111-2058; the others ended in 13, 04, 26, and 63. I've googled them all, and this one is the only one I've seen any information on. I haven't answered any of them (when I get long distance calls from numbers I don't know, I tend not to answer, because they're almost always telemarketers), but my wife has answered a couple of times, and they always ask for me, then decline to leave a message.
With reference to the "CDHA", I don't know what that is, but it isn't ringing any bells with me.