Double-sided tape residue on painted wall, how did I remove it?

I've tried everything warm water and soap , hairdryer and knife .. etc ... I need something effective . Can someone help ?

Try lighter fluid - apply some to a paper towel and rub at the residue in a circular motion.

You'll want to check the painted surface for color fastness on a suitably hidden spot first to be sure it's not going to damage the paint (although this is unlikely in my experience)