Endesa (founded in 1944) was a public company which was sold off to the private sector beginning in 1998 and finally ending up under the control of the Italian (publically owned) Enel by 2009.
...
Back in the summer of 2024, the electric company stopped sending me bills. Kind of them. I went to their local office several times, and also sent them a few emails, and was told on each occasion that the issue was 'una incidencia'.
This continued until some fellow showed up, lost, to put in a new meter, sometime about November last year. By then, I had enjoyed sixteen months without a factura.
Since then, they've been coming in fast. Sometimes quite expensive ones as they adjust for the months consumed. Some of the facturas are for two months, others for one. I've been paying them as best I can. 
Yesterday, a Sunday (!), the company sent me nine emails. They were all different bills, some for dates I had already paid, some repeated and some new.
They added up to a lot of money.
I went to the local office and the lady there says that some of them were repeats indeed, but four of them were good... and besides, there were another two of them waiting for me in her computer.
You can ask to pay them in parts she said helpfully...
I never got an apology or an acknowledgement - despite six visits so far to the regional office.
I can see myself changing to another electric supplier in the days to come.