So easily you trapped the juggernaut Tannu whom Pragya and co had been struggling to trap for months and months!!
Why do you need Pragya to have all that money, and end up hurting her Maa/BB, making Abhi lose wealth etc?
You can do it yourself.
You can tell truth to Abhi, or you can plot to expose your bahu to be!
Although you have provided Pragya with a make over, money and support, looks like you can do it easy and better than her and you have that power too as the eldest in the family.
So realize that and be proactive Daadi!!