Econo 400w heaters @Makro not a winner!

I bought the second econo wall heater, and only using the heaters in winter,it seems that there is a problem with them. My second one cracked,and because I couldn't find the box within the 3year period(it having a three year warranty), I wasn't sure on the warranty period. Nevertheless, the consultant couldn't give me details on this purchase,even after having my makro card to her availability. Wow, I thought that data management is carried on these cards. I was shocked when she told me I need to know when I bought it. How can a person remember all his purchases? I think this was the last time I got one of those in my house. I think for now I will settle for a credit note/refund. I believe we all work hard for our money, and I am not just gonna throw away money like this. X2 unlucky purchasing the same product. Mobile:***