Fast charge : Fast discharge!!

Hi there..

My iPod Touch 5th Generation 64gb (bought refurbished from Apple just weeks ago) has had battery issues from day one...

The battery charges from 15% up to 100% in 45 minutes, and then proceeds with steady use to discharge in just under 2 hours!!

I have done a factory reset and I have the brightness down below half.

Can anyone throw some light on my problem?

Cheers...

Andrew :-)