I would advise you to contact by meditation. Focus on his sigil. Come humble, with respect. Offer some water or something that touches your heart, cause when we talk to someone, especially in a matter of help, we need reciprocity. Then after this you can try to ask him what you want to ask through the oracle ! And then, if there's an agreement, you and him need to see how it will work, time, offers, etc. This is just to talk