UPDATE: Referral Client Is Demanding a Refund, Mentioning Legal Action, and the Business Owner Says This Is Entirely on Me. Looking for Honest Input.

I posted earlier about a dog that was diagnosed with a UTI after an overnight stay I completed.
For context, this was not my personal client. I was providing care as a referral sitter through another pet-sitting company. I signed paperwork stating that I was operating under their business, that the clients were not hiring me directly, and that I was covered under both my own insurance and the business owner’s insurance while caring for their clients.
The dog has a documented history of recurrent UTIs.
During the stay, I followed the written care sheet that was provided to me, took the dog out multiple times throughout the stay, fed her according to schedule, and sent the owner an update letting her know that the dog seemed a little off and that I was monitoring her. Looking back, I absolutely could have documented more thoroughly and provided more detailed updates. I have no issue admitting that.
After the stay, the dog was taken to the vet and diagnosed with a UTI.
The owner is now demanding a refund, wants the tip returned, has mentioned insurance claims, and has referenced legal action. She believes I should have recognized what was happening and done more.
The part that has me struggling is that I feel like nobody is willing to even hear my side before deciding I’m entirely at fault.
I am a veterinary assistant. Because I was genuinely questioning myself, I spoke with the veterinarian I work under as well as a registered veterinary technician. Both told me that it is entirely possible the UTI was already developing before or during the stay and that it would be difficult to definitively say that the infection developed because of the overnight care itself.
To be clear, neither of them said I handled everything perfectly. They both agreed that better documentation is always beneficial. However, neither immediately concluded that I somehow caused the UTI.
The business owner I subcontract through has essentially told me that this is on me, that she agrees with the client, that she would want a refund and vet bill reimbursement if she were the owner, and that she has spoken to other professional sitters who also agree with the client.
What is confusing me is that this same person previously told me in writing that:
I was operating under her business.
The clients were not hiring me directly.
I was covered under her insurance while caring for her clients.
I was acting as a referral subcontractor for her company.
Now I’m being told that none of this falls back on her business and that this is entirely my responsibility.
At this point I’m planning to refund the stay because I don’t want the situation to escalate further, but I’m honestly struggling with how all of this has been handled.
I feel like there are two separate issues:
Could I have documented and communicated more thoroughly? Absolutely.
Is it fair to automatically conclude that I caused a recurrent UTI after one overnight stay? I’m not so sure.
Another part of this is that I’m still scheduled to complete bookings through this sitter until the end of July, including additional overnights. Before this situation, I already had some concerns about whether subcontracting was the right fit for me, but after how this situation has been handled, I’m honestly questioning whether I want to continue working under this arrangement at all.
It’s not just the complaint itself. It’s the feeling that any attempt to explain my perspective is immediately viewed as being defensive, and that the conclusion was reached before my side was ever really considered. The entire situation has left me extremely uncomfortable and has made me question whether I want to continue representing another business moving forward.
I’m genuinely looking for honest feedback from other pet sitters, veterinary professionals, and business owners.
Am I missing something here?
Would you refund the stay?
Would you consider yourself fully responsible for the UTI in this situation?
And if you were subcontracting through another pet-sitting company, would you be comfortable continuing to work under that arrangement after something like this?