The problem is that Telefonica has a market share of more than 80%, so they don't care if they loose a client.
Fortunately this is changing and there are good companies which offer better services and products. You did the right thing by changing to Ono, it is a very good company with a promising future (the only spanish cable company which earns money).
Don't forget other companies like Wanadoo, Ya.com, Jazztel, Tiscali and Arsys. Some may dissapear in the near future or get absorbed, but the remaining ones will be in a good position.
Fernando