alaikum asalaam wa rahmatulaahi wabarakaatu

First of all,you are doing the right thing my sister,as those people who were supposed to have hired you should and ONLY have concentrated on you professional capabilities,educational qualifications and work experience,NOT at your niqab,obviously they had other motives as well,ALLAH knows best.
In the meantime,continue to apply for various companies and INSHAALLAH you will an opportunity to work with people who do not discriminate or are racist.