Your SIM will only usually save roughly 20 texts all the other will be saved on your mobile memory. As for the button, i am afraid that you are a bit stuck there. As that model has e removable cover have you tried to have a look inside, and see any obvious obstructions. I have done the same thing with a glass of coke and all it needed was a wipe down with a bit of methylated spirits, and amazingly it worked! This is probably highly unadviseable, but there you go. Most mobile phone providers insurance cover accidental damage!