phone will not let me download a app
i have been trying to re download snap chat and every time i do it pops up a screen that says there is a billing problem with a previous purchase and i’ve just been really confused cause i have not tried to buy anything on my cell phone and also i tried to update this game i have on my phone earlier and it said the same thing and it tells me to put a password to something and i don’t know what to do so i decided to come on here and ask for help can anyone help