What should one do who experiences satanic whispers of disbelief upon seeing newspapers strewn on the ground in the morning in front of a grocery store that does not open until 8 o'clock?

You must treat the whispers of disbelief and not be carried away by them. The cure for obsessive whispers is to completely turn away from them. Whoever is afflicted by them should seek refuge in Allah and desist.

As for newspapers that contain the remembrance of Allah and are subjected to disrespect, they should be placed in a way that does not disrespect the remembrance, if possible, without excessive hardship. Otherwise, "Allah does not burden a soul beyond its capacity."