Today, I bought a modem and a cable broadband connection from Telia Skanssi (Turku). They sold the modem without the necessary cable or cable splitter (which should be included in the package).

I first checked with other shops (Gigantti, Power, etc.), but could not find those splitter/cable. So, one hour later, when I went back to return it, the customer-service person behaved extremely rude! Also, he declined to cancel my broadband connection, even though the shop (Or any other Telia shop in Turku) did not have a functioning modem to sell!

So, I am left with a Telia connection (2 year contract - 540€!) for which they could not sell a proper modem, and thus could not use it. And the worst part of the whole negative experience is how rude the service provider was! 

If you have to buy from Telia, better go to Hansa or somewhere else.