Of all the methods I have tried using a natural starter/preferment, I would say that the toughest one to make work is to go directly to the refrigerator after making the dough. Jeff Varasano’s work is often cited as a cold fermentation model because the dough can be held in the refrigerator for several days (e.g., up to 6 days), but it is really a combination of room temperature fermentation and cold fermentation. Jeff uses several room-temperature rest periods before refrigerating the dough. My recollection is that the multiple rest periods are over an hour in total duration. These rest periods are really fermentation periods (since all of the ingredients, including the starter/preferment and any commercial yeast, are combined at the outset), not classic autolyse rest periods in which only the flour and water are combined and allowed to rest. Any room-temperature rest period in which the leavening agent is at work will allow the dough to warm up and get a head start on fermentation before it is refrigerated. The enzymes in the dough will work during the cold fermentation but the activity of the yeast will be reduced.
Another effective method is the one that Bill/SFNM has described in which a combination of room temperature fermentation (several hours), cold fermentation (maybe a day or more), and a final warm-up period (several hours) is used. It may be that Bill is using a different regimen these days, but my recollection is that he had great success with the above combination. Not too long ago, I used the same combination (5 hours room temperature, 66 hours of cold fermentation, and 5 hours room temperature) to make one of the De Lorenzo clone doughs at the Philly/Trenton-Area Tomato Pie thread.
When my fermentation temperature is too low, especialy below the optimum fermentation temperature of 18-20 degrees C, the dough (naturally leavened) takes forever to rise. That is one of the reasons why I bought a MR-138 ThermoKool unit. It is something that I think anyone who plans to make naturally leavened doughs with any regularity should consider. Otherwise, you are at the mercy of your ambient temperatures (room temperature or refrigerator temperatures), which can vary quite widely, especially room temperatures which are subject to wide seasonal variations. You still will have issues with the startesr used and their activity levels, but you at least take a lot of temperature issues out of the equation.
In your case, it is possible that the dough has risen but it has not been visually discernible, especially if it has flattened and slumped into a disk-shaped mass. What you may want to do is to let the dough warm up for several hours after it has been taken out of the refrigerator. If the dough visibly rises, I think you should be OK.
For some additional commentary on this subject, you may want to take a look at this recent thread: http://www.pizzamaking.com/forum/index.php/topic,5512.msg46618.html#msg46618