Need A Movie Name Please

Me & my partner are very keen to watch this movie again but only know the plot ,so here is the plot, A couple go away on holiday who are having an affair , She goes out in a vehicle to get some things she goes to get fuel & she notices a SUV parked a little bit in front of her & notices that a small hand writing on the rear window on the condensation HELP. She goes to intervene but the vehicle drives off so she decides to follow it , she ends up miles away from anywhere in a rural location , She climbs over the locked gate And walks to the house & starts looking through the windows & notices this odd couple have some children kidnapped , She goes to try & get away unnoticed but fails & gets kidnapped herself . She is pregnant so they keep her alive until she has the baby . In the meantime her partner is frantic & looking for her , Not sure how she gets away but she does but only after having the baby , It is an excellent Thriller & would love to see it again i watched it around 2017 on the cinema app on a fire stick. I have searched & searched the cinema app but cannot find it . Many thanks for your help