Hi @naitikbohra
Does the speaker still work OK when the charger is connected?
''If you can use the speaker'' but the battery is not charging it may be a faulty battery. Here's the [guide|140279] guide that shows how to replace the battery.
''If the speaker doesn't work when the charger is connected'', have you tried a different known working compatible charger or charging cable e.g. one used to charge a mobile phone?
Use a strong light and a magnifying glass to check that the pins in the charge port connector are all there and not bent or missing, that they're all straight and parallel with each other and that there's no dust or debris in the port enclosure preventing a good electrical connection.
If everything above has been tried and it still doesn't work here's the [guide|140281] guide that may help.
It shows how to open the speaker so that the charge port connector can be checked to see if it is loose from the board and only needs to be resoldered back on.
If everything appears to be OK then further testing would be required to find out what's wrong.