Some accommodations do not accept credit cards - prepayment for them should be made by bank transfer. You can check this information on the property description:
If the description of the accommodation states "Cash only" and there is no additional payment information in "The fine print", you can check the possibility of payment by bank transfer directly with the accommodation or Booking.com Customer Service.
Contact details of the property are always mentioned in the reservation confirmation.
Customer Service contacts can be found here: https://www.booking.com/content/offices.en-gb.html