Hello @Lorraine47
Sorry I don't know what 'strata rules' means. Also wasn't clear from your posts who you haven't had a response from and who offered you more expensive accommodation.
Clarifying these issues will help us provide you with advice.
In essence, if a host cancels - unless covered by extenuating circumstances, they will have penalties imposed on them. So some hosts are reluctant to cancel themselves.
If your host has let you know they are cancelling your booking, they should have followed it up by cancelling with BNB. BNB shoudl then have got in touch with you regarding a refund and also offered you a discount voucher towards new accommodation. They should also help you find alternatives that are available.
If your host hasn't cancelled give BNB a call and ask their advice. Full details are in the CONTACT BNB post at the top of this forum.