diff --git a/eopayment/common.py b/eopayment/common.py
index ac37e77..a16efe5 100644
--- a/eopayment/common.py
+++ b/eopayment/common.py
@@ -5,6 +5,8 @@ import logging
 import cgi
 from datetime import date
 
+import six
+
 __all__ = ['PaymentCommon', 'URL', 'HTML', 'RANDOM', 'RECEIVED', 'ACCEPTED',
            'PAID', 'ERROR', 'WAITING']
 
@@ -29,15 +31,27 @@ ORDERID_TRANSACTION_SEPARATOR = '!'
 
 
 def force_text(s, encoding='utf-8'):
-    if isinstance(s, unicode):
+    if issubclass(type(s), six.text_type):
         return s
     try:
-        return unicode(s, encoding)
+        if not issubclass(type(s), six.string_types):
+            if six.PY3:
+                if isinstance(s, bytes):
+                    s = six.text_type(s, encoding)
+                else:
+                    s = six.text_type(s)
+            elif hasattr(s, '__unicode__'):
+                s = six.text_type(s)
+            else:
+                s = six.text_type(bytes(s), encoding)
+        else:
+            s = s.decode(encoding)
     except UnicodeDecodeError:
-        return unicode(s)
+        return six.text_type(s, encoding, 'ignore')
+    return s
 
 def force_byte(s, encoding='utf-8'):
-    if isinstance(s, str):
+    if isinstance(s, bytes):
         return s
     try:
         return s.encode(encoding)