nether portal

[Maldk]

So this is the second time (out of 2) this have happened to me
I make a nether portal, and when I want to destroy it wont break, I can remove the obsidian, but the purple portal stays. If I go through I will suffocate since I get trapped in blocks.
Last time I had the staff trying to help me get rid of the purple portal, but with no luck.
Somehow I managed to get rid of one purple portal 'block' by using water, something like that, it was really random how I got the last one removed.
I wanted to make I new one because for some reason the portal I started to take me to another's portal and not the one at my base
I will attach two pictures so you can check out the XYZ and also getting a better understanding with what I'm trying to say :p
Thanks for taking your time reading my post
Maldk

[Maldk]

A little update, I found the way to break it, I have to place water behind the block and that will break one block, but it shouldn't be like that right?
I still have an issue tho, when I want to go back to the overworld I get teleported to someone's portal and not the one at my base

[WarehouseAgent]

The issue of going to someone else's portal may not exactly be a glitch, but a result of the tricky math between Overworld and Nether portal coordinates.

http://minecraft.gamepedia.com/Nether_portal#Portal_linkage_between_Overworld_and_Nether

Thus, for a given location (X, Y, Z) in the Overworld, the corresponding coordinates in the Nether are (floor(X ÷ 8), Y, floor(Z ÷ 8)) (the Java floor() method gives the largest integer less than or equal to the argument, so an X- or Z-coordinate of -29.5 becomes -30, not -29). Conversely, for a location (X, Y, Z) in the Nether, the matching Overworld coordinates are (floor(X × 8), Y, floor(Z × 8)).
...
First, if the portal block in which the player is standing has been used recently, then it will re-use the destination that was chosen the last time; in this sense, portals do "remember" their linked pairs, but only for about 60 seconds (1200 game world ticks, or 600 redstone ticks)
...
If the player's origin portal has not been used recently, then a new destination will be computed. First, the game converts the entry coordinates into destination coordinates as above: The entry X- and Z-coordinates are multiplied or divided by 8 (or 3) depending on direction of travel, while the Y-coordinate is not changed.

Starting at these destination coordinates, the game looks for the closest active portal...

--and so on.

At any rate, I think I read in chat once that an admin can "fix" a portal's location. If you catch one in-game, it might be worth asking if that's possible.