My LENOVO K900 phone has started giving a peculiar problem! When I put the phone for charging there's none?

My LENOVO K900 phone has started giving a peculiar problem! When I put the phone for charging(whether phone is on or off) the battery does not get charged. Sometimes I find the battery has got fully discharged instead of charging! What could have gone wrong and how can I solve the problem?

Powerpoint? Plug? Cable? Connection in the device? Battery? One or more of those is wrong.