Academic policy does not let me earn credits from certain past courses. How can I challenge it?
Edit: this answer was written based on the original policy quote.
The policy is clear, if the undergraduate course was taken to satisfy pre-requisite requirements then it can be counted.
As you clearly state that it was not needed to satisfy a pre-requisite requirement, and you state clearly that it was an elective then it will not be counted.
So, it looks like you will need to complete some credits to cover that lack.