I see a lot of ICOs hire SebastianJu , he is well known escrow between Bitcointalk members , also he is legendary and experienced member in Bitcointalk , he has a service thread in service board and this is the link:
https://bitcointalk.org/index.php?topic=1102721.0You can watch the feedback and then if you saw him the suitable one , you can contact him.
Edit: I think you want escrow to hold the money of your twitter campaign , if right , I suggest you hire a manager and he will be escrow and manager in the same time , most of other campaigns do that , you can contact Yahoo in this case .