@Maria1216 I think you should contact Air BNB and request that they intercede on your behalf. Let them know that you and your party have been inconvenience and that you want to be relocated within 48 hours unless the hot water is fixed. Also, you want a 15% refund for every day there has been no hot water, to be determined at the end of the reservation or when you are relocated which ever comes first. Air BNB will communicate with the host and negotiate between you and the host.
If the host is unable to fix the problem, it will be a host cancellation due to extenuating circumstances and you might also get a 10% credit for the inconvenience.
While problems can occur for any host, I believe it is the host responsibility to quickly resolve the problem or request relocation of the guest. Keep us posted as to what happens.
In case you need Air BNB contact information, here is a guide.
https://community.withairbnb.com/t5/Help/Contact-Airbnb-A-Community-Help-Guide/m-p/16165#M728