Problems with My Profilo Built-in Oven

I bought a Profilo built-in oven, but it seems like there's a problem with the bottom part not heating properly. So, I had this service technician come over to check out the problem, but they said they couldn't find anything wrong and just left without fixing it. I don't know what to do next. This isn't the only issue I've come across. After reading some reviews, it looks like I'm not the only one having problems with this product. I've been using it for about 11 months, and this problem has been there since we first got it. We asked for another service visit, but it didn't end up being very helpful either. I'm starting to think if I can return this product. I need some answers and a functioning oven. This experience is so frustrating.