Samsung Galaxy Trend Plus Battery Swelling

Good day<br> <br> I bought my phone from Cna In December 2014. By July my battery had swollen and my phone was unusable if not on charge. I was told by CNA that it would take 8 weeks to sort out because they would have to send it in for a check up. So what do I do for 8 weeks without a phone? I eventually just bought another battery so I didn't have to send it in and the same thing has occurred.<br> <br> So what do I do and what are my options?<br> <br> Thank you.