Rectifying Inaccurate Appraisal

Can anyone advise me what action I can take to get an inaccurate appraisal of my apartment rectified? I recently decided to refinance my mortgage in the hopes of getting a lower interest rate. The mortgage broker arranged an appraisal which valued my apartment significantly below its true value because the appraiser managed to omit the private garden, central air and second half-bathroom, thereby significantly lowering the appraised value, to the point where the refinance could not go ahead. The broker rebutted the report, but has subsequently dropped me like a hot potato and won’t return my calls so I presume he has given up on arranging my refinance. I would like to challenge the appraiser’s report, more on principle than anything else. It was a shoddy piece of work and the appraiser should be obliged to rectify his errors, IMHO.
I have written to the appraiser directly, but have received no response yet. So, my question is, is there a governing body that oversees/licenses appraisers that I could approach? Surely there are codes of ethics, standards, etc. that apply to appraisers? Any other suggestions for dealing with this gratefully received.