Similar here. AGD 10.2.0 to AGO. Submitted a support incident request this morning, but have not heard back beyond the robot's note.
After successfully publishing once this morning, I deleted the published service and items, made some changes in authoring, then went through the publish sequence again and got the errors below.
From ArcGIS Desktop ArcMap, I shared as a hosted feature service to our ArcGIS Online subscription. The resulting service appears under "My Hosted Services", but when I try to add it to ArcMap, I get "Warning: Could not add the specified data object to the map. Unable to return internet proxy for server types other than arcgis server." When I click Details for the Features item in My Content, get "Error: Item does not exist or is inaccessible. Item does not exist or is inaccessible." When I try to delete the hosted feature service from ArcMap, I get "ArcGIS Server: Error: code:400, Item does not exist in this folder.,Bad syntax in request." When I look at the REST services directory I get "Item does not exist or is inaccessible."
After about 5.5 hours, the service became available, accessible, etc. No suggestion of service outage in the AGO health-o-meter.