I've tried everything warm water and soap , hairdryer and knife .. etc ... I need something effective . Can someone help ?
I had a similar problem, but applied on a wooden door frame - I wanted to protect the door frame while painting the walls. I got the problem of glue left on the wood.
At somebody's suggestion, I rubbed the affected area with a cloth dipped in kitchen oil. There was some work, but the glue eventually came off. After that, removing the excess oil was not a big issue.
In your case, you should test your wall first, to see if the oil would damage it. Do the test in a hidden area, to be protected in case of a positive test.
I've actually used the same piece of tape to remove the stuck glue. The glue on the tape will usually stick to the glue on the surface really well, then you gently/slowly remove the tape again. Make sure you are touching glue to glue, not bare spot to glue.
Once you have the tape stuck back to the glue spot, you can also try using a circular motion when pulling off the glue. You can also try using the tape to essentially rub it glue off.
Using a mild solvent oil, like WD-40 or Goop, you'll want to keep it from touching a painted surface as much as possible, as it can damage the paint. I suggest using a cloth towel to apply the solvent to, then gently apply the oil to the whole glue spot, then rub the glue spot off gently. Using a circular motion can help. What this does is allow the solvent to get under the glue as well as preventing the glue from sticking to another section of wall as you remove it. You'll need to wash the solvent off very shortly after removing the glue, so it has less time to dissolve the paint.
You can do the same thing with a grease removing soap, like Dawn. Some soaps won't work very well, since they don't work well to dissolve the soap, but they can still help.