Go out and announce in medina that prayer is not valid but the recitation of the Qur’an even though it might be fatihat al-kitab and something more.
لِي رَسُولُ اللَّهِ ﷺ اخْرُجْ فَنَادِ فِي الْمَدِينَةِ أَنَّهُ لاَ صَلاَةَ إِلاَّ بِقُرْآنٍ وَلَوْ بِفَاتِحَةِ الْكِتَابِ فَمَا زَادَ