The Samsung GT-E2120 (a.k.a E2120) was announced in August of 2009, and later released that year in September.
It can be identified by a sticker located underneath the battery.
This sounds like a case of dead battery. Plug your phone into the charger and try to turn it on. Does it? If it does, you need a new battery. If that doesn't work, try doing a hard reset. You will lose all of your saved data, but it may recover the phone.