I'm new and I had the exact same problem as you.. About 2 weeks ago I was getting annoyed about moving every time I woke up.. I was a little sceptical about mantra's because I didn't really believe in them, but I thought I may as well give it a shot. So I started just saying one before I went to sleep, "I won't move my body when I wake up" and really believed and thought about not moving when I wake up, and to my surprise, I didn't move when my alarm went off that night. Were you actually believing and thinking about the mantra's you said?
Also, do you have a an iPod touch? Or iPhone? I use an app called "12,24 Alarm" which has an option for auto-snooze so the alarm plays for 5 seconds and I wake up and not move, and it automatically snoozes.
Hope this helps a little bit