Honestly I would contact him directly and work the issue out before anything else .... if he gives you problems (which he wont) lemme know
A few things tho on your review:
(1) - you dont need a relay kit at all. Relay kits are only required for analog/magnetic style ballast kits ..... his kit is an electronic/digital kit and you do not need a relay .... he is 100% correct by stating so.
(2) - Remember, almost all ballasts are made from one of less than a handful (thats five, count em) of companies ..... its almost garunteed that the ballast from your old eBay kit to your new one is made from the same manufacturer.
(3) - My kit which was the same 5000k H7 kit, had the rubber grommet's .... you should have contacted him.
(4) - You state that there should be a HUGE difference between 5000k and 10000k and to correct you if your wrong. Well, your kinda wrong

To your naked eye, its very hard to see a huge noticeable difference from the two .... its not like the night/day comparison from comparing halogens to HID's. There is a difference however mostly its on the technical side and something the naked eye is not going to catch by staring at the lights. The main/large difference that you will see is the color ..... the subtle difference that is most noticeable when doing road tests is the light output (hard to see when staring at your front end). Please read up on the differences between the temperatures of kits and you will fully understand.
(6) - Color should be white with a hue of white/purple but more white than anything. Mine kinda looks more of a white/purple hue from the drivers seat and white/blue hue from other drivers.
In the end .... I think you have an extremely isolated problem/issue and you need to contact kickxtc directly and get them rectified immediately. Electronic devices can get damaged from shipping ... this is not a new thing my friend. It was produced in China, shipped to some intermediate warehouse, than off to the US, to another warehouse, and than to your door ... things happen sometimes and thats why everything insured. Let us know what he says and what happens.
~croat