Hey, I would suggest you to not use any fat burners, it would be of no help and will have side effects infact. It’s so great that you lost 20 kgs in a year, it’s amazing!
So the only thing that helps in weight loss is being in a calorie deficit. Eat fewer calories. That’s all that will help. You can also maybe increase your cardio like walking more/running/cycling etc. That will also increase the deficit you are in. 
All the best!