There are a number of factors that can influence this problem:
1st - Check the encoding of the text being saved by your text editor; 2nd - Check the coding that is being used in your browser (test in several browsers to make sure the problem is really in the database); 3rd Check the encoding of the database;
4th - Check the encoding of the tables; 5th - Check the encoding of table cells that accept characters;
In extreme cases use functions, either javascript, php or your preferred language to force the bank to enter and exit in the correct encoding.
I recommend using UTF-8 encoding, which is currently the most used by browsers.