I have a borla X-pipe with 4 resonators and mine is pretty much like that at the x section. I don't have problems with o2 sensors, but the X section was definetely going to rub on the Crossover plate... so i ended up not putting the crossover plate and making a different bracket that kind of bends down more so it will bypass the x section.
I only paid 400 for my borla x-pipe so i didn't mind making it work... you on the other hand paying over 1k and still having an issue is understandable. Hopefully you get your money back.
2010 Audi R8