It should work the same either way. Most likely the issue is the return redirect using www. when your site doesn't or vice versa, not an issue with the type of payment.
The best solution is probably to either force www. or force not www. using an htaccess rule.
#Force www:
RewriteEngine on
RewriteCond %{HTTP_HOST} ^example.com [NC]
RewriteRule ^(.*)$ http://www.example.com/$1 [L,R=301,NC]
#Force non-www:
RewriteEngine on
RewriteCond %{HTTP_HOST} ^www\.example\.com [NC]
RewriteRule ^(.*)$ http://example.com/$1 [L,R=301]