Hello @Anthony1336 and welcome to ABB CC from across the lands and oceans in Auckland, New Zealand.
What a most unfortunate situation.
Do you clean the property yourself or have someone in to do the cleaning?
It is sometimes an idea to take photos between Guests and when they have checked out as a backup.
Maybe the smell of the bleach was too overpowering and that is why the Guest said it stinks, perhaps you could message them to seek clarification as to what the smell was that they are complaining about?
It is optional if you wish to refund any of the fees they have paid to stay in your property, however be mindful you have the right to not make any refund at all as you have also been equally disadvantaged in not been able to re-advertise the property to make up for your Guest/s deciding to not stay.
With your policy being a Strict Cancellation there would have to be concrete reasons to request or follow through with one.
Best to keep things amicable and 'Focus on Future' Guests.
Be mindful you do have Right of Reply should they write a review, meanwhile perhaps be pro-active and address the matter through the message system if need be.
All the best