Bad Service on repairs

I recently brought a Sony M2 Aqua on cell C contract and the phone didn't last a week I sent it back for repairs and it took more than a month for the phone to come back and finally when it did, it lasted for 4 days and had the same problem again and I returned it back for repairs. I've been paying the phone for 2 months and it doesn't even last a week with me. I receive 1gig every month which I don't get to use and expire because the phone is not with me and the store didn't offer me a phone which I can use in the time being. My main concern is my personal information I get to loose each and every time I send the phone for repairs. I can't be paying for something i am not using.