Dell — problem with battery back up

Hi sir this is ram Naveen and I just want to raise a complaint regarding with my battery back up.I just bought my laptop in last September butdue to iam in another city I didn't used it properly.But when I came back to laptop it has been running down its charging very quickly as it can.That too it has been happened in 4 months.So I had the warranty to m laptop also.So I need the immediate change of my battery for my future work.I will be remained as a very good customer of yours.Even my computer monitor is also the dell.Thank you sir.I will wait for your reply my contact NO:[protected]