I've bought a used Blackberry Curve 8520 but problems

Hi all

I recently purchased a used Blackberry Curve 8520; it was from eBay and the seller included a brand-new battery and charger.

The problem is that I've been charging the phone for about 2 hours now and it still won't switch on.

There's a red light on the Blackberry that comes on about 3 or 4 seconds after plugging in the charger then it goes off after about 30 seconds.

I don't even know if the phone's charging or not. Is this normal and how long should I give it before there really is a problem ?

Thanks in advance.