Lydia, it is unfortunate what you are going through with your tortoises. I do not keep this species, so am unable to offer any care advice. However I do have some suggestions that you may find useful, with respect to herp transactions in general:
- When there is a problem, notify the seller immediately, if for no other reason than to document that there was a problem when it was received. The seller has no control over how the buyer keeps the animal, and what may happen to the animal, days or weeks down the road. They are naturally going to be skeptical when a problem is brought to their attention a month later.
- If you are buying wild caught herps, always assume that there will be health issues. They go through a great deal of stress before you receive them, and even if the seller has them active and feeding, they should be seen by a qualified reptile vet. Also assume the animals have internal parasites, and have the vet do a fecal check. There is always a risk of loss or health issues with any herp, but especially more so with wild caught, despite everything you and your vet do.
- When you contact a seller with a problem, be clear, concise, and courteous. This is no different than returning an item at a retail store- you get better results when you don't immediately take an adversarial approach. I'm sorry, but in your texts, you gave an impression of being combative very quickly. Your urgency was clear enough, but it was also clear that the seller wasn't immediately able to text you detailed husbandry advice.
- Although a good seller will generally be willing to give husbandry advice, don't rely solely on them. Take it upon yourself to thoroughly research the needs of the given species. With a commonly kept species such as Russian tortoise, you should be able to find lots of information without having to rely on the seller.
- Do not demand information that really isn't relevant to the transaction. Many businesses do not give out information such as where they purchase the products that they sell; herp sellers are no different. Knowing the sellers source in Ukraine isn't going to help your tortoises.
- When the seller offers a refund or replacement, just accept. You are unlikely to ever get more than that. I realize you were just looking for advice, but it should have been clear that you weren't going to get it; at least not by text, then and there.
- If the seller misrepresented the animals, present them with the evidence to that effect, preferably in a non-accusatory tone. (Tagging your post with "wildlife smuggler" is not likely to be productive) Maybe, instead of being out and out fraud, it was a miscommunication on somebody's part. In this case, these sound like wild tortoises that nobody knows the true age of. I don't personally know the seller, but I don't know your vet either.
If I were in your situation, I would accept the sellers offer of a refund or replacement. I would research proper care of Russian tortoises, including discussing it with other hobbyists who have experience with this species. And, if necessary, I would consider getting a second opinion from another reptile vet. If dealing with these sorts of problems is more than you want to get into, I would also recommend buying captive bred specimens only from this point on.
Good luck.