Why not cast Angad as Anukalp's replacement?

However, for me this is not the same show but another one. Some fans need to realise that because they have great chemistry on one show does not mean that they have to be together in everything. That was more likely why they casted Nishant and Sujay in the first place.

And if that was the case, why didn't they just cast Angad as Nishant's replacement if they wanted that particular pairing?

I am guessing that this was not the case so I'm not sure why all of a sudden the producers want to put Aditya and Mona together simply because they had great chemistry on another show.

Thoughts on this.