Why doesn't Inserting data from Json Object work?

I don't know why insert values in my table doesn't work using foreach to traverse Json Object.. when I see the table, fields are empty.

Json Object (from jquery.ajax)

[{"marca":"Cisco","producto":"UCS","subproducto":"Nexus"},"marca":"Citrix","producto":"Networking","subproducto":"Netscaler"}]

print_r($data)

Array
(
[0] => Array
    (
        [marca] => Cisco
        [producto] => UCS
        [subproducto] => Nexus
    )

[1] => Array
    (
        [marca] => Citrix
        [producto] => Networking
        [subproducto] => Netscaler
    )

)

PHP CODE

$data = json_decode($this->dataNewPoliza['alcances'], true);

$marca;
$producto;
$subproducto;

$sqlAlc = "INSERT INTO t_poliza_alcanceproductos VALUES (:idp,:m,:p,:s)";
$resultAlc = $this->dbConnect->prepare($sqlAlc) or die ($sqlAlc);

foreach ($data as $key => $value) {
    foreach ($value as $mps => $valuemps) {
            if($mps == 'marca') {
            $marca = $valuemps;
        }

        if($mps == 'producto') {
            $producto = $valuemps;
        }

        if($mps == 'subproducto') {
            $subproducto = $valuemps;
        }
    }

    $resultAlc->bindValue(':idp',$id_poliza,PDO::PARAM_INT);
    $resultAlc->bindValue(':m',$marca,PDO::PARAM_INT);
    $resultAlc->bindValue(':p',$producto,PDO::PARAM_INT);
    $resultAlc->bindValue(':s',$subproducto,PDO::PARAM_INT);

    if(!$resultAlc->execute()) {
        return false;
    } else {
        return true;
    }
}

Hope to get some help.

Solved

The problem was that I could not do return false or true within the foreach and as said @zerkms , I don't need nested loop, and this is final result:

$data = json_decode($this->dataNewPoliza['alcances'], true);

$sqlAlc = "INSERT INTO t_poliza_alcanceproductos VALUES (:idp,:m,:p,:s)";

$resultAlc = $this->dbConnect->prepare($sqlAlc) or die ($sqlAlc);

foreach ($data as $key => $value) {
    $resultAlc->bindValue(':idp',$id_poliza,PDO::PARAM_INT);
    $resultAlc->bindValue(':m',$value['marca'],PDO::PARAM_INT);
    $resultAlc->bindValue(':p',$value['producto'],PDO::PARAM_INT);
    $resultAlc->bindValue(':s',$value['subproducto'],PDO::PARAM_INT);

    $resultAlc->execute();
}

return true;

Thanks for ur help!