Very rude employees. Why do they not accept banknotes where there is a small seal, barely noticeable, also if a small figure is written on the banknote with a pen, although they check the banknotes they are all real, there are no jambs, but despite this they do not accept them anyway.
The exchange rate is about the same as in all exchangers, but in banks it is usually better. Look for the exchange rate in banks, and preferably on the stock exchange.