Mastercard Corporate Card - Include 16 Digit Card Number in Payment

Hi,

We have recently implemented corporate cards with our client, who use Mastercard.

The card issuer has recently contacted us to say that they are unable to match payments made without a reference of the 16 digit card number for the card billing unit on the payment.

Has anyone faced this issue in the past, and what steps have you taken to resolve this?

Thanks,

Alex