Submit expense claim for $0 or less

Summary:

Hi We have a long running issue in our cloud solution where we are unable submit Zero dollar or negative expense claims.
this is due to a refund to the card or sometimes fraudulent returns and this can often result in a total expense claim amount of $0 if the original transaction and the credit are there together, OR a credit if the original has already been acquitted.
In the normal state of business, we ask the users to keep the credit until they have more charges on their card but sometimes a user has no more transactions and is leaving the department.