Insurance changed provider Tier without notifying

Hello!
My wife's insurance changed a provider from Tier 1 to Tier 2 on January 2023, without us notifying. We were undergoing IVF with this provider since May 2022 and she switched companies in Fall 2022. We called our insurance to verify that this provider will still be a Tier 1 with the new company, because she was the only Tier 1 provider in the network and we had no other alternative at that time. The insurance verified over the phone that the provider will remain Tier 1 and same benefits will apply. The provider is also well aware that we only continued treatment because we wanted to take advantage of the Tier 1 benefits. So we continued with our treatment. However, the egg retrieval process occurred in the first week of Januar 2023 and we got last week our bill with a Tier 2 charge. I mean, how much more can or could we have done to ensure that our provider will be Tier 1? The insurance says that they have records indicating that they told us that she is Tier 1 with the new company but are stating all we can do is appeal.
Does anyone have experience with such a situation or can provide advice? Do I need a lawyer?

submitted by /u/SatisfactionNo5778
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