My thoughts are she was dating some other guy and got pregnant. The other guy wasn't very rich so she dumped him. Ticks why she HAD to get Married to shashwat that very day, so she can pass off the pregnancy as his. And lthe mystery phone calls being received are from her ex.
I know I know this sounds like a plot of one of those horrible saas bahu soaps, but the current track seems to be taking this drama in the same direction.
What are your theories on Monikangna. Do share.