Posting mail from Myanmar to Europe takes about a week (if sent from Yangon). Sending mail from smaller towns takes longer and is not always reliable. In principle, all incoming and outgoing mail is checked so it could be that mail does not always arrive or arrives open!
International calls can be a difficult in Myanmar, but you can (sometimes) make calls from the Central Telephone office in Yangon. That is the cheapest way but it may take a long time before you are connected. The larger hotels in Yangon, Mandalay and Bagan have a direct connection with foreign countries. The rates are steep. In the interior of the country you can only connect with larger cities. The international country code for Myanmar is 0095. Calling to/from a mobile phone is not possible.
In Yangon, Mandalay and Bagan you can occasionally receive and send e-mails. Sometimes you must do it via the email address of the hotel or Internet cafe, sometimes you can use your own email address. The cost of this service is also high. Yahoo and Hotmail addresses are unusable in Myanmar. The government puts a lot of restrictions in place to limit the access to information for the citizens in Myanmar.