New cellphone - not working

Good day, I upgraded my cell phone contract and received a CATB15Q cell phone. From day one the phone keep cutting of after about 3 seconds whilst you are talking on the phone and cease up. Since today the handset has been in twice for repairs. I received it back last week and is still having the same problem, cutting off whilst on the line and the phone cease up forcing you to take out the battery to reset the handset. I requested Vincent to replace the handset several times but keep sending it for repairs. I am prepared to accept a different make for the same value. Since the first week in January 2016 when I received the handset I could not use the phone without any problems. Please help me in this regard as I am very frustrated and unable to use my phone for the intended purposes. <br> <br> Thank your<br> Mr. Charl Heymans<br> CG Waterplan<br> <br> <br> Vodacom outlet: Mookgophong<br> Vincent ***<br> Cell no. ***