Is it true that my prayer is not accepted if I leave the prayer area after the congregation and before the Imam moves, and I have not completed the remembrances?

The prayer of the ma'mum (follower) is not invalidated by omitting the adhkar (remembrances) after the prayer or by departing before the imam (leader) moves. We do not know of any scholar who said that the prayer is invalidated by this. The meaning of "departing" (al-insiraf) in the hadith, "Do not precede me in bowing, nor in prostrating, nor in standing, nor in departing," refers to the tasleem (salutation) from the prayer, meaning, "Do not say the tasleem before the imam says it." It is mustahabb (recommended) for the ma'mum not to leave his place until the imam turns away from the direction of the qiblah. However, if the imam deviates from the Sunnah by prolonging his sitting facing the qiblah, or if he turns away, then there is no harm for the ma'mum to stand up and leave him.