Tired of going back for the same problem

I have sent my tablet Sony Experia Z1 in for the same problem twice now I am sending it back for the third time. It was 8 or 9 months when it started giving problems, the speaker doesn't want to work and the on/off button. They say it's software problems, it breaks lessons than two months every time they \fix"it. I hardly ever use my tablet and it's still on contract. I am very disappointed in this bad service. Trying to make excuses for poor products and services.. Now they have sent it in again and it will come back the same way it came.. So tired of this now.."""