Idiot Doctor. If he left the tube that attached to the Band from the port, that could create a big problem for you. You need to see him ,and DEMAND that he remove it. You should NOT have to pay anything out of your own pocket for this.
A band "cutting" the stomach is rather unlikely, but it can happen, and has happened. It is more likely the problem was erosion, however the medevac part of the story might suggest something different, something more acute. Hard to say from that info.
Well, that is one of the hazards of the Lap Band. It is very easy to defeat. If your "bad eating habits" have always included soft and slider foods, then you are gonna have a problem with the band. Restriction will only help just so much. A lot of people who have the band are not told about this when they sign up for it. And if they are, they often don't listen.