

Am I being taken advantage of?
Went to his regular vet for not eating a week prior and the vet suggested he may be almost (pre?)diabetic and suggested a diet change. He went nuts for wet food /pate when offered to him and he seemed great. Fast forward a week plus some days to Friday afternoon and he's laying on the floor, his eyes unfocused, very weak.
Regular vet said they were too busy to see him and to take him to a Veterinary ER. We took him to the closest place which is 45 minutes away. After some tests they determined he has feline DKA. They presented me with a 10k estimate and I hesitated and asked them to take it to the next 24 hours and see how he does. On Saturday he wasn't much better so I said ok to the 10k estimate.
Sunday morning the ER calls saying they talked to a more specialized ER in town and think he will do better there and he won't cost much more money. I settle out at over 8k and take him to the other ER.
Upon admission at the other ER I am asked to approve an estimate between $7.9k and $13.2k. I didn't know what else to do, so I approve it. I'm sick over this, his annual max on his pet insurance is $5,000.
Today he is doing better, still not eating on his own yet. I told them I am maxed out at 10k with them and they are acting like that might not be enough. I feel like I've been beat up, this cat is my best friend, are they taking advantage of that? I know many of you have been through this, any advice is welcome.
Screenshots of the final invoice from the first place and the estimate from the current place.