If it were the correct "T", and there is no defect in it, and you are using the proper sized snake, it should go around the corner without "bending" the snake. WIthout knowing whether you are using the proper snake, accessing the drain in the proper location, we cannot help you. BUT, if you are snaking through the toilet's opening, then it is almost impossible to get the proper snake to turn downward, because its natural tendency will be to make a "U" turn and go UP the pipe. An undersized, or weak, snake CAN make the "S" turn necessary, but will seldom do a proper job of clearing the obstruction, which could be why it happens every 6 months.