Keep some Peroxide on hand. Our pet injested D-con and wife's uncle who's a vet recommended pouring peroxide down until it induces vomitting. The dog was fine afterwards and no vet bill.
X2 on the peroxide. I have 2 labs that get into everything. Last week our pup got under the kitchen sink and drank some Pine Sol - and we have child proof cabinets. Down with the peroxide and up with the Pine Sol.
I also take them wherever we go and only rent at pet freindly places.
For me personally, I would be upset and would probably want a refund and some compensation as it was rented as pet friendly. But I understand things happen. The vet bill seems a little steep though unless it was an emergency vet visit. Youre doing the right thing by contacting them and lesson learned on the poison.
Lesson learned for the owner's too though. When we stay somewhere the dogs are in their kennels most of the time and are also trained not to go on furniture unless invited up. My theory is that you're in someone else's property and it needs to be treated better then your own.