Why won't my BlackBerry Curve 9320 charge?

hello, ive got the blackberry curve 9320 however i could not find the precise mobile on here.... a few months ago the police took my phone, i just got it back today and it just will not charge no matter how many times i try. i plug it in and a red light comes up and 5 seconds later a battery with a lighting bolt comes onto the screen which means its chargin then about 10 seconds laters it changes to a battery with a red cross through it.... could you help me and let me know how i can maybe fix this and just get it charged so i can turn it on becos then i can make sure its never switched off....... i know its not the plug and i know that before hand my phone used to work perfectly