Whirleybird., this is NOTHING new.....This "trick" have been done forever!!.
I am almost sure those guys where indeed Edenorte workers, with "free" time AFTER finishing a real job....You didn't expect someone at Edenorte to say they were, did you?...."Covering their axxes" comes to mind.
I lost count of the times a person has asked one of those workers (electricity, cable.....etc.ect): "hey listen, when you are finished with my neighbor, can you fix mine, there's a propita for you"....Only to have the guy say "ok, I'll be back after work".
Pretty simple: WHOMEVER shows up at your house to fix ANYTHING, call the company they say they belong to, to verify.....ANNNND ask them to show you some type of identification.
Definitely see your point... a bit like the guy in UK who used to have some tarmac over after fixing the road and did a cheap job late afternoon on your driveway!!! Despite the identification, the answer has to be verify, verify, verify and with the telephone number YOU have and not the one they give you or dial for you, eh?