Had two BBLs and both times, the fat did not survive. What am I doing wrong?

I had 2 bbl 2 years apart. The latest one was just 3 weeks ago. The first time my butt look good for only 2 weeks. The doctor said he only tranffered 300cc which seem no where near being enough. Once the swelling went down it was right back from where i started. And now I'm 3.5 weeks post (BA, lipo to arms, flanks,back and abdomen transfer 500cc each cheeks) and i can already see my butt going flat again. I followed all of my PS instructions but can't get my fat to survive. What am i doing wrong?