I tried with the service gatewayapi & bulksms.com which are integrated with wisecp,
I spoke with support and was told to add the UCS2 encoding to the code lest it be corrected
i add 'encoding' => $UCS2, in file class.php but i get error when i send sms Array ( [fields] => Array ( [encoding] => Array ( [0] => Array ( [scalarinvalid] => Not a valid value ) ) )
I also added manually to the code to send a specific message, whatever you send, but when you put Greek characters, the same error comes out