Deductible payment at office but was told no copay [NY]

I think this is a dumb question. I recently switched my health insurance plan from a high monthly low deductible to low monthly, high deductible. I also haven’t been to a specialist in a while.

I made an appt with a dermatologist and on the phone they said “you have no co-pay for this visit”. I went yesterday and they told me I have to pay $100 to my deductible. There were signs everywhere saying “Starting January 2024 you must pay $100 to your deductible”.

I know there’s a difference between the copay and deductible, but is it common knowledge to know you’ll have to pay x amount towards your deductible if it hasn’t been hit? I tried messaging my health insurance a few weeks ago asking amount expected and they said “pre-determined by doctor” Why would they mention copay not deductible when they had signs everywhere?