Dental Insurance claimed to be in-network

I found a practice on my insurance page that said in-network. After calling the office, I was told they were in-network as well. Following a first visit, they suggested a few procedures (root canal on one tooth, crown on another). After estimating the charges at the front desk which seemed reasonable (~$400) I agreed to the procedure. By the time I go to the next visit, they quoted me a different amount which they told me I had to pay up front (~$1500). I should have questioned them more and asked for a breakdown first. Instead I paid and expected that I would later be credited after they submitted the insurance claims. They send me a credit card receipt after calling twice without the itemization. There was a third visit as well, in which they told me I needed to pay an additional $500.
A little too late, I started following more closely. I found out on my insurance page that the doctor who saw me is not in network. When I called them up, they said he was in network at the time of my first visit but fell out after that. This was a false statement as I later found out through my insurance that the doctor hasn't been in network since earlier this year. When I confronted the practice, they also told me that I was informed he was out of network. I wasn't at any point.
My additional mistake: they told me they required my signature on a pad. I assumed it was a consent form for procedures. After asking them for treatment plans last week, they sent me 4 different ones ranging from $400 to $2400 with my signature on them. The first one with $400 is dated on my first visit.
What are my options here? Knowing that they misled me, communication with them has been awful. I still don't know the exact breakdown of the $1500 they charged me for and they promise emails or documents which they don't share.