getPaymentProfileId() vs getCustomerPaymentProfileIds()

[jobs2careers]

What is the difference between getPaymentProfileId() and getCustomerPaymentProfileIds()? When should I use which?

I teste using this code:

$rsp = $req->createCustomerPaymentProfile($customer_id, $payment, 'testMode');

$payment_id = $rsp->getPaymentProfileId();

but sometimes $payment_id is "" (i.e. empty string).  I also tested on production server with 'liveMode', and the result is the same.

Should I use getCustomerPaymentProfileIds() even if I only add one payment profile?  The name suggest that the function would return an array of paymentIds, but when I tried it only returned one scalar value.

Since I can't find any document on either function, can someone please explain when to use which?

[RaynorC1emen7]

I think is depend on how many payment profile id that customer profile id have.

[jobs2careers]

That's what I thought to, but unfortunately that's not the case.

I only created one customer payment profile, so I thought I should use getPaymentProfileId(), but it's returning empty string.

[RaynorC1emen7]

Look to me for createCustomerPaymentProfile, use getPaymentProfileId because there is only one allow for each call.

And getCustomerPaymentProfileIds for createCustomerProfile because you can do multiple payment profiles.