Where do I begin?

I need help. Help with bra fitting. Last week I went to Bras N things (Perth store). I paid $45 for a maternity bra. According to measurements I am 10E. I always thought I was 12B. Anyways the bra doesn't fit right. My breast comes out a little . I just don't know what to do. Does anyone know of bra expert I can go to in Perth besides from Bras N Things?