It is not the ISP. The word ISP comes with the Internet.
In this country it is possible for people to get so-called 'förval'. There are so many companies to give you telephone facillities.
In the good old days, if I may say so, it was a single company who handled the telephony. It was a government or rather a semi-government organization.
"Service provider" doesn't always mean 'Internet Service Provider'. It is common in North America that the companies that provide utility (Electricity, Cable, Telephone, Gas,etc.) services would be referred as "service providers".