Coast Dental Services review: Overcharging for services, made to pay upfront, refusal to submit charges to secondary insurance even though an in network provider

They advised my husband would need to have a deep scaling and infection prevention procedures to a tune of $1,346. We paid this upfront and now they are threatening to turn our claim over to collections because they refuse to file with the secondary insurance which is a requirement of Blue Cross Dental. They agreed to be an In Network provider. It's a requirement with Blue Cross Dental that all dental charges first go through BC medical and then submitted to BC Dental. I don't make-up the rules and they agreed to this by wanting to be a BC Dental In Network provider. They refused. So much of these INFLATED charges are being denied. You CAN'T reach them on the phone, EVER. I've driven 40 miles 3x to try and work this out. The billing person is pleasant but ineffective. The receptionist is downright rude. We won't go into the sanitary conditions of the office. I've spoken to BC Dental directly and was told we've overpaid by $583. In the meantime, my A+ credit is going to be marred by their fraudulent practices. I just went in for an annual cleaning and x-rays (completely covered). I was made to pay a $23 payment on the spot and am now being turned over to collections $201. I'm supposed to get 2 cleanings per year free as part of my dental insurance. How is it I owe $201 for one cleaning? Mine complaint is much the same as many others I've read. How are they able to get away with this. What do I need to do to have this issue resolved?