My experience with vets here is that the standard of care is very good; I would bring someone who speaks the language with you to speak to the vet so that you understand exactly what has happened. If you can't do that, ask the vet who cared for your dog to send a report to your vet - and speak to him/her.
If I understand the law correctly, a vet has the
duty to intervene and to do what is necessary in his professional judgement if the situation is critical or the dog is suffering.
I would be thankful that the kennel staff intervened in a timely fashion.
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What did you sign when you put your dogs in the kennel? I would imagine that there is usually a standard clause allowing the staff to bring the pet to a vet for treatment when necessary. Think of it this way - they have likely saved your dog's life.
And a note to everyone using a kennel or a professional dog sitter, or a relying favors from neighbors - as well as to all who are offering pet sitting services:
You must discuss how emergencies will be handled well ahead of time.
Set up a contact protocol, and set up an agreement as to what should be done if for some reason you are not contactable. You should also discuss the finances around emergency care. You should notify your own vet if your dog is in the care of a third party, and if it is agreed that the third party would bring the pet to a vet other than yours, before traveling you should take it upon yourself to meet that vet and make sure that he/she has a full medical history for your dog. And - discuss the worst-case scenario with both the vets and the sitter. Unexpected illness, life-threatening emergencies can happen at any time.
You should also leave a summary of your pet's medical history with your sitter or with the kennel.
Additionally, set up a regular contact schedule while you are away. Whether it is daily phone calls, e-mail, skyping with your dog

, whatever.
(And when you are hiring a sitter, make sure you ascertain that person is prepared to act in an emergency.)
I've said this a million times, but... caring for pets is not a casual job. Yes, the work is relatively easy - but the responsibility is very great indeed.
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Hope your dog is doing better now. But do make sure that you speak to the vet who did the surgery so that you understand what happened.