I still think it was Ayesha that kidnapped Ritvhik. From Ayesha's point of view, Prachi is Ritvhik's mother, and no mother can stand to be apart from her child, from Ayesha's POV, Prachi will be worried as hell, so Ayesha must have thought that Prachi may blurt out in the heat and stress of the moment, 'I am Ritvhik mother, my bacha is kidnapped' and blah blah.
I am dead sure it is NOT Miland who got Ritvhik kidnapped, but I think everyone may point fingers at Miland as he is maha miffed off at NP, so the shah house may assume that he had go the baby kidnapped too just to get back at NP. I think even Prachi may well misunderstand Miland too😕 I think the creatives will make it look as though Miland got Ritvhik kidnapped, but in the end the real culprit's face will be shown.