***Warning***
I'm going to go out on a limb here.
All telephone based promotions are IVR (Interactive Voice Response) based. They essentially interface with legacy systems (read IBM mainframes/clones). All transactions are based on screen scraping programs. Many of these applications are non-transparent to end-users (read Frontline personnel)
So, give it time ;-)
[PS: In my shop we've used many of these IVRs and IWRs interfacing with many systems - It is non-trivial. Sometimes bugs crop up that were not anticipated]