How do I fill an area relative to the players position

Question

[MINECRAFT 1.8.9]

So I have an endportal constantly spawning 4 blocks above the player with this command:

/execute @a ~ ~ ~ setblock ~ ~4 ~ minecraft:end_portal

and I want the portal to disappear when I move one block away in any direction from it so that it "follows you".

So I have these commands running on a fast clock:

execute @a ~ ~ ~ fill ~-3 ~ ~-1 ~3 ~ ~-3 air 0 replace end_portal

execute @a ~ ~ ~ fill ~-3 ~ ~1 ~3 ~ ~3 air 0 replace end_portal

execute @a ~ ~ ~ fill ~1 ~ ~ ~3 ~ ~ air 0 replace end_portal

execute @a ~ ~ ~ fill ~-1 ~ ~ ~-3 ~ ~ air 0 replace end_portal

These are supposed to remove all endportals around you but not above or below your current position

For some reason it's not working

Answer 1

I forgot the height in these commands:

execute @a ~ ~ ~ fill ~-3 ~30 ~-1 ~3 ~ ~-3 air 0 replace end_portal

execute @a ~ ~ ~ fill ~-3 ~30 ~1 ~3 ~ ~3 air 0 replace end_portal

execute @a ~ ~ ~ fill ~1 ~30 ~ ~3 ~ ~ air 0 replace end_portal

execute @a ~ ~ ~ fill ~-1 ~30 ~ ~-3 ~ ~ air 0 replace end_portal

I added 30 to the Y of each of them.