What can i do about my phone?

k so i am with koodo. i have the samsung elevate. it glitches on me soo much. i could be halfway through a phone call or text and it will just turn off then back on. i get so many texts late. i was told that the texts late was because i have a sim card and there trying to work out the bugs? but the glitching? pretty sure its the phone. i went in to trade it, and they told me i would have to pay for it and i dont have money in my tab.