Family Orthodontics

We are retired grandparents on SS raising our granddaughter since infancy & whom we adopted in 2007. She is now 17. Her 4 front teeth were overlapping. We were told she needed a 2 year treatment plan. Prior to end of plan the overlapping was corrected but now there was a space between her two front teeth. Our pymts were $150 a month & that was paid faithfully every month. She was in foster care prior to being placed with us so she was on Medicaid/no Ortho, but a benefactor gave a gift for orthodontic treatment thru the State for foster children and adoptees, but I would need a letter from the Orthodontist saying she was getting treatment. The office refused saying they didn't take Medicaid. I tried to tell them it wasn't Medicaid, but a GIFT and the State would be paying them DIRECTLY! They still refused. Braces broken again in 2 places; she's in pain! Asked them to remove braces, but they won't without $360 PLUS cost of retainers! I missed a few apptmts & they said I owe $1,200! How??