Is a double-enty only valid for 3 months and the duration of each entry is just one month?

im planning to use the service of a travel agency (Uniorient) but they informed me that a double entry visa is only valid for 3 months. and the duration of each entry is just one month. Are they telling the truth? they said the rules of the embassy always change. I'm planning to file the application personally but i am not sure what are the REAL requirements. Uniorient Travels only asked for my passport, pix and filled up app form.