Droid2 has a mind of it's own!?

my droid 2, which is only 4 months old, is so messed up. sometimes it's perfect, and sometimes it's the worst. the battery only lasts about 1 hour, and it might be because the cord in the charger has a slice in it, but it's already my second charger in 4 months. and i stepped on my phone (lightly) this one time, but it was fine after. but lately it clicks places on it's own, calls people, tries to unlock it on it's own (which sometimes makes me wait for 30 minuets because it tried to unlock it too many times) and it takes me about 10 minuets to send a one word text. i brought it in, and because i have one scratch on the corner, they wont give me a free one back. what should i do? i don't want to pay an outrageous amount of money. and yes, i know. i am very clumsy. :P