Medlife — automatic blood pressure monitor

I ordered this product (Automatic blood pressure monitor) in around april. I have been observing high fluctuations in bp readings since then. Intitially i ignored but the difference in readings increased.
Also now the battery is drained up within 4-5 days. I have used 3 new sets of 4 cells each over last 3-4 weeks.
I have already complained on customer care and didn’t get any further response. It is in one year warranty. Please resolve it as soon as possible.