We recently hired someone to fix a hole in our drywall, they matched the texture and just told us to sand it and prime it before patinting. We did all that and painted the hole wall but after we painted it you can still tell where the hole used to be, how do we fix it?

What can you see? A difference in color? Try a stain blocker such as Kiltz and then touch up with the same paint. If it is higher or lower, it could be your sanding. One way to make sure things like that don't show is to shine a bright light parallel to the wall and look for any shadow. Now that it is painted, it is tougher to sand.

Actually KILTZ = KILZ
Another really good block coat is SECRET UNDERCOVER AGENT

But then, this does not answer the posted repair question...

If the wall repair is uneven, it will need to be remudded with joint compound... NOT Spackle or Dap.
To do the flat work is easy if you own an 11" mud knife.
1. If the paint surface is not a gloss enamel, then sanding preparation is not necessary.
2. Dampening the surface will test out the existing texture and give a wetted bond to the mud being applied.
3. If it is a small area, then applying a palmfull of joint compound(premixed and stirred to get rid of air pockets) shaped in the center of the blade will give a smooth surface that will fill uneven voids. Keep the rocker knife at about a 30 degree angle to maintain a smooth pass.
4. Once the flat surface is coated, leave to cure until the mud turns white.
5. Now this surface will shrink slightly so flat sanding is necessary. Use a carpenter's level to checkout the surface trueness.
6. To match the existing wall texture, an mud texture application gun is needed. There are low cost texture sprays-in-a-can that will work cheaper than renting an application rig.
7. Practice on a piece of sheetrock to see how to get the texture to match what is on the wall.
8. There are two common textures that are simple to apply, orange peel and knock down.
9. The best way to match the wall is to visit HD or Lowe's and those guys usually have decent reference samples in the lumber department where drywall is sold. Some stores will assist you in what must be done to get good results.
10. Once the texture has dryed DO NOT SAND or even wipe the surface. It will break down easilly.
11. Next a drywall sealer coat or primer can be rolled on or sprayed. One roller coat needs thorough drying.
12 Apply a second coat and let that dry also.
13. Make an effort to feather the edges to blend in with the existing paint surface.
14. Now the final paint is ready for application. A roller works good. Spraying even better.
15. Let dry to see if the paint matches the original coating and there was sufficient primer. Two coats should work.

Let dry and you are good to go... nm