You have to make sure that the content encoding for your web pages is UTF, otherwise it is not going to work. Here are few tips:
1. Make sure the datatype of your data in database table is nvarchar.
2. Make sure that the SP you are using also has nvarchar as parameter type.
3. Make request and response encoding as UTF-8. Add this in the web.config for application level encoding:
<configuration>
<system.web>
<globalization
requestEncoding="utf-8"
responseEncoding="utf-8"
/>
</system.web>
</configuration>
and add this for page level encoding:
<%@ Page RequestEncoding="utf-8" ResponseEncoding="utf-8" %>
And as SA said we don't know what did you screw, this probably is just few suggestions that might work. Try and come back if it helps.