name=%D0%98%D0%BB%D1%8C%D1%8F;phone=89213251626
$arr = explode(';', 'name=%D0%98%D0%BB%D1%8C%D1%8F;phone=89213251626');
foreach($arr as $item) {
$tmp = explode('=', $item);
$array[$tmp[0]] = $tmp[1];
}
$arr = null;
$returnValue = parse_str('name=%D0%98%D0%BB%D1%8C%D1%8F&phone=89213251626', $arr);
//результат
array (
'name' => 'Илья',
'phone' => '89213251626',
)