Question:

I want to ask you if maybe someone know, How to get visa if I send all documents from other EU state over the post to Iranian embassy in Vienna? How I can pay visa? How they send me back confirmed passport? How much cost this visa and How long take?

Answer:

I assume that you have a reference number of visa to Iran and now you want to collect it form the embassy. Usually, receiving the docs back by posting those to an inbound Iranian embassy takes about 1 working week but in your case it may take longer.
First of all you should call the people in the embassy to make sure about the status of your visa then pay them in a way they instruct you (these details may be available on the website too) and finally post your docs.
The best way to apply for Iran visa is to fill in the visa form on Iran visa application, it takes about 3-7 working days to get your reference number and two working days to collect your visa at the embassy by direct referral or one working week by posting the docs to the embassy. You can pay the visa fee in cash in Iran.