Why did they replace rahi in anupama ?

I was quite interested in the show when alisha played the character of rahi but after they replaced her the new pair has lost its charm. The new rahi looks way too old for prem . And I know alisha was also not a great actor but the new rahi is just intolerable her acting is way worse than hers. Like the chemistry is just not their. And after the reports of rupali ganguly exit from the show in near future . I think this will be the last year of the show which once started pretty good but ended in a absolute shit show.