You need to clearly enumerate your itemFilters. You have at least 2 versions of itemFilter(0).name= with MaxPrice overwriting your Condition filter. You also have an itemFilter without an enumeration at all (itemFilter.value=FixedPrice), probably altering things as well. Take your time to build those filters carefully 1 at a time.
Also, while you're at it, have all the itemFilter's together in your URL, in order, and at the end of the URL (in other words, move the pagination params and sortOrder before all itemFilter params). I've seen cases where this matters.
Also get your SERVICE-VERSION= to be current -- 1.12.0 . That can only help.