Major plot hole (SPOILER)
When Victor calls Jack's mom on the phone he says that "Jack is an old friend" or whatever and keeps calling him Jack, his mom is responsive to that name. Now the problem with this is that 5 minutes later when they are in the hotel room, "Jack" tells Victor that isn't his real name and he isn't going to tell him his real name. I guess you could go waaaaay out on a limb and say his mom was in on it with him BUT then why would she give the info to him? Just so he can go kill him and try to get the money back.
If it wasn't for this plot hole, Victor would have never gotten any info from "Jack's" mom and she would have just told Victor he had to wrong number. Bottom line is that he wouldn't have gotten the information to find him and Jack probably would have gotten away.