Commision on final cleaning

We received a Mail from Booking.com that will also be calculated from 1 September on the additional costs such as final cleaning commission. I think that Booking.com is abusing its position on the market here. We are a small B&B and cannot easily cancel at Booking.com, their position is too large. We have no problems become money for their activities, but those things such as final cleaning or breakfast service, which we already have minimally calculated (so as the most others i think) we are going to put money on it that mains we have now choice, we need to raise prices. Anyway, at the beginning of this year we were already saddled with 1.2% costs on payment transactions and now again at least 12% on the extra costs. I wonder if it is better not to ask for ancillary costs directly on arrival of the guests and not via Booking.com.
And what comes next?