Unfortunately I don’t believe that you can write off the $2500 investment. In return for your investment, you get a 25% share of the profits that the business earns. The fact that you put this on your credit card just means that you have a liability of $2500 to the credit card company but that is not a tax deduction. However, the interest that you have paid on that $2500 could be tax deductible. I recommend you contact a tax professional to find out.
To locate a tax professional, check out this article:https://fitsmallbusiness.com/how-to-find-a-quickbooks-proadvisor/