Self pay cost was quoted at $700, they’re trying to get me to pay $900, is this legal?

So they’re trying to charge me

$346.80 for dermatology , $346.80 for PCOS visit 1 , $230.80 visit 2 = $924.40

They’re telling me that prior to the visit they told me that I received the initial self pay estimate was:

$250 for dermatology , $434.00 for PCOS visit 1 , $309.20 visit 2 = $993

so I’m paying less than initially quoted. But the only thing I received via email was this quote for visit 1 and visit 2. There was no mention of a dermatology appointment being billed separately. They also only did a partial visit for the follow up since the psychologist got sick, so I think the reduced charge is due to this.

Self-Pay cost is $434.00 for the first evaluation by REI providers. Self pay cost for the 2nd and 3 month follow-up evaluation is approximately $309.20

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Is there anything I can do to argue with the charge? I called the hospital to confirm the payment and was ok with the $700 price tag, but I’m very frustrated with the surprise dermatology cost. Are hospitals legally allowed to not tell you initial costs up front like this? There was no way for me to know that dermatology would have a separate cost from the first visit. None of these appointments were surprise or emergency visits, everything was planned 6 months in advance.