Bad debt

I loaned 15K with 8% interest to a business I was an Advisor. The relationship soured and I was removed from the company. With interest that is documented it amounts to 18K. I have engaged a lawyer and written several letters all to which she has not responded with any payments. I wrote to the SEC but since its not a public company, they said its not them. At this stage I have tried and clearly its not getting repaid. 

 

How do I claim? Can I claim original 15K

Can I claim interest owed and documented? Up to end of 2024 since claiming on taxes?

How do I actually claim..which form and what do I detail. IRS says have show tried to collect..I have that 

 

Looking for advice on the above