List available phone number blocks

{
    "data": [
        {
            "cost_information": {
                "currency": "USD",
                "monthly_cost": "6.54",
                "upfront_cost": "3.21"
            },
            "features": [
                {
                    "name": "sms"
                },
                {
                    "name": "voice"
                }
            ],
            "phone_number": "+19705555000",
            "range": 10,
            "record_type": "available_phone_number_block",
            "region_information": [
                {
                    "region_name": "US",
                    "region_type": "country_code"
                }
            ]
        }
    ],
    "meta": {
        "best_effort_results": 50,
        "total_results": 100
    }
}