Keypad wont work. I use a SE K850i... been using it since January, but for the past 2 weeks, each

Question

I use a SE K850i... been using it since January, but for the past 2 weeks, each time i text, i press one key but something else pops up. say when i hit 5, what comes up is the writing options... also the "soft touch" button on the left doesnt work. i have to turn it on and off , it'll work for a time but not for long. i tried the master reset, no change. help!