I bough u a microven and is still under the warranty

I bough u a microven and is still under the warranty.I took it back to game store i west gate mall on the 7of February because it is not heating.When i got there the consultant did not give me any reference that i can use to follow up.i called the shop today and was told the microven is not yet attended to.there was no email or sms that was send to acknowlege and that they received the item.when call today i am beingbtranfered from one person to another.even the manger could not help me.No procedure for was explained to me that I I Must follow.What does the Popi say and it was not app**** .m under the the impression that they are sort this out.