Clean sticker paper residue off of a wall

This problem is on a wall in my bedroom. I used to have a A3 paper sized photo stickers on my wall. After a year or so I tried to remove the sticker from the wall and it left lots of sticker paper remains and adhesive residue on the wall. I tried to scrape it off with a scraper but it didn't work.

I went to a hardware store and told the guy working there of the problem I have and he told me to buy a sheet of sandpaper and a bottle of thinner. As per his advice he told me that I had to apply the thinner on the wall and scrape it off with the sandpaper. Though it didn't seem logical to me, since he was much older than me, I thought maybe he's got experience with this and there's no harm in trying this out so I bought the thinner and sandpaper from his store. On coming home I tried doing as he said but it ended up looking much worse. (See image)

I got busy with work and it i did not get back to addressing the problem.

Today I found this community on stack exchange and I was thinking, surely the people here would have much more experience than me so I thought I'd ask here.

Is there any product or method to remove the paper mess and adhesive residue from the wall without damaging the paint?

Edit from orginal-poster: I read in the comments that someone was mentioning a product called GooGone. But we dont have that in India. If you could give me a kind of name/product to ask at the hardware store it would be helpful. Thanks.