Telefonica / Iberbanda are terrible companies to deal with.
Even the staff in our bank here, have had problems with them. Our solicitor has a pile of letters and demands, which these companies keep sending out to his clients.
He even told us to ignore any communication from them now!

I think the majority of people find Nigel very helpful.
The Eurona, usually works very well, for most of us.
It does go down sometimes, in bad weather, or if they are doing maintenance work. On the whole it's good.
Could it be something to do with your electricity supply, fluctuating, that causes some problems, maybe?