How can I add new cancellation policies?

I dont think you can if you only have one payment type  and not  2, non refundable and refundable ( flexible).

as for seasonal, that is not a thing, but you can toggle offf one rate plan for a date or range of dates, to which any and all cancellation policies would apply if for the same rate type that is active.

REMINDER : NEVER POST ANY ACTION REQUEST , ESPECICALLY CANCELLATION REQUESTS HERE, NOTHING WILL HAPPEN., EVER!

Simply report to BdC Partner Support , see below 3 methods.

Message or Call BdC PartnerSupport ***

1. In the extranet, go to the ‘Inbox’ tab.
2. Select ‘Booking.com messages’.
3. Right Pane - Click on ‘See Contact Options’. 
4. Choose Account
5. Now choose Other
6. Then at bottom , See all contact options, and click Message or Call
7. As there is no one number for all partners, the number for your nearest BdC Partner Support is then revealed.

8.  

   *** public main lines via Where you can reach us

    

    

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