Doctor recommendations for treating hypertension in Bengaluru

My mom recently had a high blood pressure 180+ twice along with severe headache in last 2 months. We visited 3 doctors so far and none of them were able to provide her good treatment not they were able to tell us the root cause. She used the medication prescribed but the blood pressure is still high and headache still persists. If you know of a doctor/cardiologist who treated you or your family members on issues related to hypertension and had good results please let me know. Or if you are a doctor, would be great if you could recommend some good doctor in your circle. Thanks in advance.