Metal Gear Solid Portable Ops passwords aren't working...

[bigbrain_biggerego99]

Hi, all. I recently got a copy of Metal Gear Solid Portable Ops (And + ) and I went on a cheat site to aquirre some passwords. I tried them but none of them worked. I am pretty sure I am not doing anything wrong. I have made sure not to do anything wrong (Do it in capitals, add the right number of spaces--if any are needed). They aren't working.
The date is the 7th January 1971 in the game (If that means anything) and I have completed it once.
Thanks in advance.

PS I have asked this question before but no one answered--This is just a type of reminder...