Plugin to verify/reject if a number code is in a database

Hello!

I am looking for a way of having vendors validating a product code for a gift certificate (physical certificate that is) on my website and I can’t figure out if there is a WP plugin for this task.

The process I had in mind would look something like this:
1. customer buys gift certificate that includes a 7-10 digit/letter code
2. customer contacts the vendor to use the certificate and gives the code
3. vendor logs in to the website and types in the code and in return gets one of three replies (accepted, rejected, already used).

I get an excel document with the codes for each gift certificate by the producer so I will need to be able to update the database on the website with each new batch of certificates produced.

Is there a plugin that can do this or be tweaked to? I have tried to search around without luck so any help is greatly appreciated =)

Thanks in advance!