The Urban Dictionary defines Soz as
Soz: Nonsensical Internet slang term for "sorry", used by illiterate morons who for some reason substitute a “z” for “rry”, the latter of which would take an entire quarter of a second to type out.
Urban Dictionary: soz
The Language page gives the text of an email using "soz" to thank me for this website, "this site is actually quite rubbish as there is to much writing and less pictures i dont even understand it ok soz but thats the truth"