really bad mixer!

I bought the mixer for the then relatively good reviews - now I can not even comprehend it.
For one thing, the mixer works only when to vegetables or fruit is filled enough liquid, the knife must be very b edeckt. if mans tried without liquid fritter unpürriert remain under the knives or at the glass edge stick side, and the blades rotate into the void. That's probably not a big deal if you want mixer especially smoothies and make banana milk with because you need anyway much liquid, but if you him (like me!) Wanted to use especially for porridge range is rather annoying.
I think that depends on that of the glass container at the bottom of the cutting blades is not narrow enough tapers mixinhalte can slip through under the rotating blades, or laterally past.
Second, does the mixer even in optimal conditions - and I've tried everything: Filling amount varies between solids and liquids varies Size varies, let him mix really long ... - in any case, even under the best conditions creates the mixer only so about 80 %, that is, stay a few lumps always left; the slide stop at the beginning by this cutting blade, and if the rest is mashed, the content is again liquid to puree to fritter ...
it is of course possible that I am doing the wrong mixer.
I had never before a mixer, it would be logically considered theoretically possible that all the mixer have this problem. maybe it gitb simply no mixer, the paste-get in a moderate time of under one minute things.
or, of all my mixer is broken, all other mix properly?