Hero Electric — Battery replacement problem

I have been using a hero electric scooty since 3 years and before 3 years i was facing some problem with battery(back up reduced).After that I visited hero electric dealer(Jorhat, Assam) and given complaint and they told that to replace the battery in free of cost as the warranty was not finished.So, as per them I replaced the battery with new one.But after 45 days battery has gone faulty and now my warranty period is over and as per technician I have to buy a new battery.Now I am very much disapointed with your service because how can a new battery will dead within 45 days.
So, I hereby request you to look after this matter as soon as possible to resolve my issue.