Can i get my phone replaced

ok i got the samsung slider from at&t the lime green one it worked good but when it slides up there is something under neath it and it makes it harder to slide up then i was was trying to call my friend and that didnt work so i texed her and it she didnt get it and she sent me one and i didnt get it so then the calling on it is messed up my sister has the same phone and she got it replaced 3 times becuz of it then i was at the pool i was wet when i cheacked it and know the sticker on the back is white/ red more red on the white sticker and so i was wounder if at&t can replace my phone with a new one