Outrageous, but there must be people who pay this amount otherwise they wouldn't try.
For PR lawyers, I have heard that they charge THB 100,000 per case. Since they cannot do anything but ask you for the documents you can get the list in English free from Immi), and you have to get the docs by yourself anyway, I keep offering my services. So far, nobody has paid, maybe I need a law degree for credibility? 🤣
Anyway, THB 700/month would not be worth it for any lawyer, because the charges for writing the invoice and doing the tax accounting in a law firm is probably more than that. So, I am not convinced of that person's credibility.