In Austin, Texas, Dr. Elisabeth Potter is trying to keep the doors of her surgery center open. She says not being able to get into Unitedhealthcare’s network could bankrupt the center and that she believes she is being retaliated against for social media videos critical of the insurance giant. Unitedhealthcare says there was no retaliation and that its surgery center network in the region was closed when Dr. Potter applied, well before she posted any videos. NBC News’ Priscilla Thompson repo