Did you go to the Support FAQ
and type in "Editor Rank" then follow the "Click here to send us a request to upgrade your editing rank" link? It asks for a few fields worth of information. In "More Details", I've always been very specific in stating that I am Level [x] with whatever number of current edits and would like upgrade to Level [y].
It has only taken me a few hours max to get a response from Waze Support, and it reflects in WME shortly thereafter.