MR2100 battery unable to charge 1%

Partner used the M2 without having power supply attached to unit.

As a resultr its now deep discahrged battery says 1% turn unit off allow to charge before using.

I can't turn unit off power button nor can I charge the battery as a result. 

I went to the service provider still under contract (Telstra) however weren't too interested told me to remove battery operate the unit that way.

Tried this only gives more warnings that battery has been removed and broadband data has been diabled as a result . 

Is there a sepearte charger I can obtain to allow chargign of the battery independently or do I now have to purchase a new battery instead ?