Hi, it’s quite possible that your provider is using a modified version of the Dhru GSM API. We’ve had that happen with a few providers.
They make custom changes to the API, for whatever reason, making it so that the only way you can interact with them is either directly on their website or re-writing code that will fit their proprietary configuration.
If your tests worked with http://reseller.stockunlocks.com then your configuration is fine, according to the Dhru specification.
In the end, you will have to communicate with your provider directly to verify.