Credit card token is not unique

Hello!

I followed the instructions in https://developer.payeezy.com/content/tokenize-creditdebit-cards-and-store-permanently, but I notice an odd issue that I'm getting different token values for the same credit card. Here is the code:

<?php

$curl = curl_init('https://api-cert.payeezy.com/v1/securitytokens?apikey=d1DvXr7d6kiPR1H0jqrH3A2pBLUo92Qk&js_security_key=js-cd191fdcf2925415a2047661efbf3e1fcd191fdcf2925415&ta_token=NOIW&auth=true&callback=Payeezy.callback&type=FDToken&credit_card.type=visa&credit_card.cardholder_name=JohnSmith&credit_card.card_number=4111111111111111&credit_card.exp_date=1030&credit_card.cvv=123');

curl_exec($curl);

curl_close($curl);

?>

Is the endpoint https://api-cert.payeezy.com/v1/securitytokens still valid? Can you please explain why I'm getting different token every time I try?

Thanks in advance!

Vijay