oppo phone asked to select language then powers off

so the battery was flat but i still could power on it and it did but instead of my lockscreen, it was a page where they ask to select language and instant recovery i think and i went to choose whatever was on the top but nothing happened so i tried to power off it but it didnt work until a few seconds later. after then, i cannot open my phone altho its charging its been the same for more and an hour someone please help asap !! thank youu