Данные в указанной вами ссылке не являются допустимыми в формате JSON. То, что вы предоставили, похоже, является расшифрованной версией. Вы можете сказать, что это не JSON, потому что ключи массива не заключены в кавычки. Например, версия должна быть «версия».
Ваши данные должны выглядеть примерно так
'{"version":"0.6","reqId":"requestIDnumber","status":"ok","sig":"65724392","table":{"cols":[{"id":"A","label":"slug","type":"string", "pattern":""},{"id":"B","label":"name","type":"string","pattern":""},{"id":"C","label":"email","type":"string","pattern":""},{"id":"D","label" :"nsid","type":"number","pattern":"#0.###############"},{"id":"E","label":"theme","type":"string","pattern":""}],"rows":[{"c":[{"v":"mo"},{"v": "Mohammad Taheri"},{"v":"email@yahoo.com"},{"v":"2929292.0","f":"2929292"},{"v":"blanc"}]}]}}'
$json = '{"version":"0.6","reqId":"requestIDnumber","status":"ok","sig":"65724392","table":{"cols":[{"id":"A","label":"slug","type":"string", "pattern":""},{"id":"B","label":"name","type":"string","pattern":""},{"id":"C","label":"email","type":"string","pattern":""},{"id":"D","label" :"nsid","type":"number","pattern":"#0.###############"},{"id":"E","label":"theme","type":"string","pattern":""}],"rows":[{"c":[{"v":"mo"},{"v": "Mohammad Taheri"},{"v":"email@yahoo.com"},{"v":"2929292.0","f":"2929292"},{"v":"blanc"}]}]}}';
$data = json_decode($json);
print_r($data->table->rows);
// выход
Array ( [0] => stdClass Object ( [c] => Array ( [0] => stdClass Object ( [v] => mo ) [1] => stdClass Object ( [v] => Mohammad Taheri ) [2] => stdClass Object ( [v] => email@yahoo.com ) [3] => stdClass Object ( [v] => 2929292.0 [f] => 2929292 ) [4] => stdClass Object ( [v] => blanc ) ) ) )