A registrar is at all times obligated to provide a token or authorization code to the lawful owner (the registrant) of a domain name. The registrant can be found in the WHOIS data.
If you are a holder, or trustee, then you can retrieve the token or authorization code with your current provider. If the provider still refuses to provide you with the token or authorization code, a holder can consider to start a procedure at the registry. If you wish to do this, please contact TransIP support via the Control Panel.