For me he works everytime when it comes to getting someone to contact you.
What I usually do is find a prayer for him. Light a white candle and read the prayer out loud a few tilmes. After that I just imagine that person texting me and blow out the candle.
The person the intended prayer was for contacted me within 48 hours each time.
Would be nice to read if anyone else have asked for different causes with him.
When all else fails or I am making a personal choice not to bother certain spirits with certain things I go to Saint Expedite, I always negotiate his payment upon the fulfillment of my request, always paying him (usually with somekind of coin payment though not always) but always a public acknowledgement and thanks towards him as well as a poundcake at an altar dressed and dedicated to him.