Great Expressions Dental Centers

Yesterday, I went into this office for a filling. I recently have been having problems with eating and a sore tongue (weird). I also was charged $128 for the procedure, but when I spoke to my insurance, Humana, they said my co pay should've been $105.
I also have an account balance of $150 for god knows what. I have called several times to discuss these issues, and no one is picking up the phone. I am very, very displeased with the services I have received here and I am not getting my hard earned money's worth.