Kidney stones are of four types: calcium oxalate stones, struvite stones, uric acid stones or cystine stones. Potassium citrate is used for the treatment of stones. I would suggest you to get an evaluation done from a urologist to determine the type of stone. Treatment modes include Extracorporeal Shock Wave Lithrotripsy (ESWL), uteroscopic stone removal and percutaneous nephrolithotomy. Since ESWL was not successful, the other two treatment options can be considered.
I hope it helps. Take care and regards.