carbocation: you confused 2,3,4-trihydroxy-benzoic acid for galic acid (= 3,4,5-trihydroxy-benzoic acid)
pink_dust_angel: you confused methylenation (forming -O-CH2-O- on catecholes) with methylation (forming -O-CH3 on phenoles) which would yield 3,4,5-trimethoxy-benzoic acid