should Muslims believe in Pir's?

Amil is someone who does chillas and other sort of amals to control jinns and other creatures.
Once u say belief. do u mean believe the information they give u when u ask them something or believe as in follow them?

In my own knowledge, a dervish (buzurg,fakir,WALI-ALLAH)lives in a world filled with supernatural beings like spirits and jinns etc, and he communicates with them. About others I now have to search for some ayat or hadith about communication with jinn