Dentist Lied About Pre Determination

Tomorrow I am getting my permanent crown/veneer combo on 8 and 9. My dentist received pre determination from guardian 12/31/24, stating insurance would not cover #9 but would cover #8 (crown). My insurance does cover veneers if deemed necessary and not just for cosmetic reasons. My dentist recorded #9 as being worn, old filling with possible decay. I called the office Jan 9 and asked if they ever got my pre determination back and they said yes and that insurance would cover both teeth at 50% so l then made an appointment I went in for first service Jan 14 2025 and was told this morning insurance actually won't be covering both teeth and only 1. I asked why they lied before and the front desk lady said she talked on the phone with the insurance and that they said they would cover both but there's no paper trail for this. Is my dentist liable for providing me with misinformation? What should I do. Should I complain and ask for them to charge me less ? I understand insurance information can be different than treatment plan numbers, or even pre determination numbers. However, there was no basis to tell me one thing that was a complete lie to get me to go through with the service and then switch up after the fact. I unfortunately don't have the call recorded.