You could try taking the heel fitting off and looking up the inside of the mast with a torch to sort out the twist. When re-threading a broken halyard I use a 2-300mm length of bath plug chain (available B&Q) attached to a mousing line to drop the line down from the sheave. Hook the chain out from the appropriate exit in the heel with a hooked piece of wire. Keep the other halyards tight during the re-threading to avoid tangling. I’ve never had a problem with internal twists/tangles.