I have about 4-5 different flange sizes for the PIS Advanced backpack. I have replaced all parts, but it still isn't adequately removing my milk. It's so bad that I solely hand express but I can't keep this up while trying to get my baby to nurse again. I had the pump checked a few weeks ago and suction is perfect. The person at the nursing store pretty much just told me that some woman quit responding to the pump. Is this true? Is there a way to trick my body?