When buying tickets, how to contact?

When buying tickets or booking hotels, how to contact?

Most of them don't even have e mail address.
If there is a phone number isn't it international call ?
International phone call are really expensive.

Buy train tickets at the station (or reserve online in some specific cases). To book hotels, the easiest way is to use a booking platform like Booking.com or Rakuten.

See http://www.japan-guide.com/e/e623b.html

When buying tickets or booking hotels, how to contact?

For sales? If you prefer to contact them directly you can call the number listed on their website. Most probably don't offer English language booking over the phone however. Otherwise, go with internet bookings as already mentioned. Far easier, faster and more reliable in most cases.

Most of them don't even have e mail address.

Most have email addresses, however whether they can handle English inquiries is another question.

If there is a phone number isn't it international call ?
International phone call are really expensive.

Yes, Japanese businesses have Japanese numbers which would be an international call from overseas. But use something like skype with prepaid credit and you can call extremely cheaply. Sometimes for even less than a local call in your own country.

99.9% of hotels have booking/reservation systems now. These can be found on their websites.

How do you book in your own country or travelling to other countries? Internet?

Also, a phone call is a lot less than your travel to Japan (just for perspective), and the cost of accommodation is also high. If you are worrying about the cost of a phone call, the cost of a trip to Japan is going to be a major problem.

Call or visit Japanese or Japan travel agency in your country.