I have had electric serviced from Endesa for more than 12 years. About 4 years ago I signed up with endesaonline after having been cut off on several occasions for non payment. I used to have direct debit but even that did not work as sometimes the bill was not paid for whatever reason, but there was no record of it even having been attempted to be withdrawn. So I used to pay manually at BBVA using an automatic teller and cash on the second (registered demand) as the first bill would arrive with a bill payment expiry date due before the bill arrived!. The same problem with Repsol, the Spanish post is sometimes very slow.
Anyway the online system worked quite well for several years, the main advantage being that you can see which bills have not been paid according to the system. Those familiar with all the utilities in Spain know that the monthly or bi monthly bills NEVER show a statement of account, or even an acknowledgement that the previous bill has been paid. If you do not have online access , it is sometimes a good idea to call the Freephone number to check if there any outstanding bills (according to Endesa) on a fairly regular basis.
With regards to Endesaa online, suddenly , for no good reason, the online account said I had no contracts associated with my account! I have tried for more than 12 months to get it reinstated, I started receiving paper bills again. Phoning the 800 number, even if you do get through to an English speaker, is of no use. They do not have any connection with Endesa online. Endesaonline can only be contacted, online!. Whilst the site is in English, any email automated response is in Spanish. There is supposed to be a complaint procedure but you cannot get the number online that you need to file a complaint. No wonder Spain is in such a poor state if they cannot even sort the billing process out for major utilities at the same time as taking more than 20% in VAT. At least in the UK we have a choice of supplier.