That was what I was not sure about- Not having a command line, it is hard to be sure exactly what is going on. Is Meraki tech support able to access the IOS to get more granular? A sh isdn would be awesome!
Do you have a rep, mine is awesome if I have any issues at all he gets them sorted out then and there. But I usually don't have issues with the techs if I ask them to test our fiber they do and send me the results, so I can see how things are running at each site and they can usually tell me if there is a issue and if they can fix it for me with out me having to go to the site as I am a dept of one. One reason why I am trying to switch to all Meraki so I can see everything and do a lot more with out having to drive every where. Sorry they aren't nicer to you.