Your ex has still not forgotten -> ... (about) you
t’habiteras plus chez tes parents -> you will no longer live with your parents
Lâche pas la patate -> hang in there!
Tout c’que t’as tu l’as mérité -> You deserve every bit of what you got
Rappelle-toi -> don't you forget that
steplait oublie pas -> please don't forget
"steplait" is just the ubiquitous "s'il te plaît"
Qu’tes théories sur le chakra sont legit -> that's the continuation of the previous line
"please keep in mind that your theories..."
which one you believe -> ...in
leur expliques des affaires -> "affaires" just means "stuff" or "things" here (girls like it when you look brainy/savvy, basically)
C't original -> it is original/creative to...
Fak steplait oublie pas -> same as before, with an extra "thus"
aussi beau qu’la moyenne -> as handsome as...
You have more problem -> "plus" means "no longer" here.
It's hard to tell from written French but it will be pronounced "plu" when meaning "no longer" while you can clearly hear the ending "s" when it means "more".
A wise man said "Language is to express; why have words in your head, when they can be heard?"