

How do I fix this issue
I've been learning to solve a cube because my 7 year old asked. Followed a guide, learnt the algorithms and stuff and last night pretty much had it solved but I made 1 crucial error.
Today however, I cant seem to get the white side solved with each side having the small upside down T correct. Currently I have the red and orange good, but the green and blue center sides have the correct colour on bottom row, but the corners are wrong.
Im not sure if my kid has turned the corners or if that would even cause this. Any suggestions?
UPDATE: I solved it all through way until the yellow was done and the 4 corners still did not match. Was indeed impossible. Had to take out a screw and re-install that layer correctly. No idea how they got mixed up it was impossible to take it apart without taking the screw out.