How to dispute an office visit bill?

I went to a dermatologist that was shown on my insurance website. I came well on time, and I had to wait for more than an hour for the doctor to come. It wasn't even the doctor that came, it was some Asian female with a bachelors(his assistant???), even though I made an appointment with the doctor himself. The whole 10 minutes that she talked to me was basically a sales pitch..... I told her the products that I have tried on my face and she basically suggested benzol and sallycilic acid(which is what I have had used before?)... She had seemingly no skin treatment expertice and didn't help at all, or even suggest anything but the creams that they were pushing to sell. Now, three month after the horrible sales pitch (for yeltin and acanya<- slightly stronger benzoyl and sallycilic acid and costs over $300 for a month supply) I get a bill! $91 for the office visit with a description of OFFICE VISIT, INTERMEDIATE LEVEL IV DEDUCTIBLE & CO-INS.....Now before and after the visit I have asked the receptionist what my co-pay would be and both times she told me 0, as on my insurance card it said Office Visit: 0..... Now, I would have no trouble with paying if I actually received some help or advice, but why should anyone have to pay for a horrible sales pitch? Is there anything that I can do about this??? BY THE WAY... I CAME WITH SIMPLE FACIAL ACNE, HOW DOES A SUPPOSED SKIN SPECIALIST KNOW NOTHING ABOUT ACNE? ALL THE SEEMED TO KNOW WAS TO PUSH PRODUCTS THAT COST OVER $300 WITH INSURANCE???