Do you have spare keys? Your family will need to use these to access the property and let the guest arriving today into the property.
Next step, decide if you will change the locks or are happy to just cut replacement keys; whatever you decide action ASAP in order that the new guests have keys when they arrive
Contact the guest who misplaced the keys and inform them of your decision i.e., new locks or cut keys. I note you do not have a security deposit which would have covered you in a situation as such since you would have been able to claim the cost of any repairs from the guest. However, dealing with the situation as it stands, inform the guest how much it will cost you and that you would expect them to cover the cost. If guest agrees then you can charge them for additional costs via the resolution centre. If they don't then you can contact Airbnb re the situation and try submitting a claim to Airbnb via the host guarantee route and hop it gets approved.
It is very important that all communication regarding this matter with this guest is done via the Airbnb platform because text messages, WhatsApp, personal mail etc. is not considered acceptable evidence of communication for Airbnb.
Can I suggest as well, that you cut spare keys for every room internally and externally which uses a key so that you are never locked out. Also it would be an idea to add a security deposit.
Hope your family can sort it out in your absence so you can get on with enjoying your holiday,
Ama
