2013 Help needed: EVSE/Charge Cable no longer covered under Voltec warranty?

So my 110V charge cable/evse got the dreaded "won't disconnect from the charge port" problem and broke when I wrenched it out. This is a Gen1 2013. Apparently this part "used to be covered under the Voltec warranty," but now they have decided as of Jan 1, 2018, that it is covered under the bumper-to-bumper 3/36 instead. Can they do that? Change after the vehicle is in service what is covered under the warranty? Is the service manager/part manager at Weseloh Chevrolet in Carlsbad, CA misinformed? Should this only apply to new vehicles?

Any help would be appreciated as I'm trying to figure this out in real time...

Larry