request to payment gateway with ssl certificate . open_basedir restriction in effect. File(/cert) is not within the allowed path(s)

I gonna to integrate payment gateway . My site located in vitural hosting. I'm sending curl to payment gateway to get from them payment url.

$data = array(
        "amount" => $request->amount,
        "currency" => 'KZT',
        "merchant_order_id" => 12,
        "description" => 'payment',
        "email" => $user->email,
        "name" => $user->name
    );
$headers = [
        'Authorization: Basic '.'YXRhbXVyYTopoPzQncxeDk=',
        'Content-Type: application/json',
        'Accept-Language: ru',
    ];

$url=$client->request('post', 'https://sandbox.com/orders/create',[
        'headers' => $headers,
        'form_params' => $data,
        'cert' => ['/cert', 'bDsc1F2fmNeK']
    ]);

Here I sending basic auth and ssl . My certificatation located in storage/cert.pem

cert route is Route::get('/cert', 'ProtectedController@getcert');

and getcert method is

public function getcert(){
   $path = 'cert.pem';
   return Storage::download($path);
}

First question is : Is this safe to store certification in storage and access it like this ? Can anyone download it if cert path will be revealed. Next question is I'm getting error

file_exists(): open_basedir restriction in effect. File(/cert) is not within the allowed path(s): (/var/www/vhosts/site.kz/:/tmp/)

as I understand Storage:download wants path storage to be in open_basedir . I asked hoster I cant change open_basedir in virtual hosting . Am I need to move to vds or there another way?