The problem can be because of two reasons, first the sensor that checks the battery level is having some malfunction or something went wrong with your on-board electricals. We will advise you to call your service center and schedule a check-up for your car. So, the problem can be fixed as soon as possible.
We are sorry to hear about your physical condition and we would suggest you to buy Mahindra e2o as its an electric car and we are suggesting you this because Mahindra Reva's production has already been stalled by the company. It is no longer available in the market. Currently, there is no Mahindra Reva Dealership in Guwahati. So please try to contact the nearest Mahindra Dealer, they might arrange the vehicle for you in Guwahati.