In Germany and the UK, contacting customer service of a commercial company is usually free and easy to do. Not so in Spain.
Even if you want to contact a Spanish company you will have difficulty contacting them for free, and probably have to use a phone number which starts with 901 or 902 where you have to pay for the call by the minute. For a ten minute call, you would be paying about one Euro for a “902” number (the most common number). Annoying, if you are trying to do the company a favour by reporting a leaking water main, for example. Particularly annoying when I lose my phone and internet connection and need to inform the telecoms company by mobile phone – that 10 minute call costs over 5 Euro. That happens about once a month at the moment – where I live the only telecoms service available is a WiMax (radio WiFi) link to the Castle in Xàtiva, and it doesn’t seem to be particularly reliable; this week I have just had an internet / phone outage of over 28 hours.
Contact via internet isn’t much better. Again, usually the only contact information on an internet page are a 901/902 phone number and maybe a contact form which you can fill in on their webpage. No postal address, no other contact information. Recently I reported an error in the online banking system of one of the biggest banks in Spain using the contact form on their website. After a week they wrote back by email to say that they could only process the error report if I sent them my tax number and my user-id for their banking system. Both are completely irrelevant in respect to the error I reported. Sorry, I can’t be bothered to provide the information they requested, so that error will probably never get fixed, and they will continue to provide a poor service via their website.
By the way, you can sometimes avoid using 90x phone numbers in Spain: there is an unofficial service at nmn900.com, which lists alternative “normal” phone numbers. Many people have a national flat rate for their phone, which makes these numbers truely free, whereas the 90x numbers produce costs to the caller even if they have a flat rate phone tariff!