My guess is, is if you felt something was truly wrong with the kit, you would probably get your money back. And I'm not saying that's the right or wrong approach. I do know Brewers Best are generally good kits. I've used them. I've even purchased them at clearance prices knowing they were old and still produced decent beer.
Brewing comes with a learning curve and it's been said by some much wiser than me, that to brew good beer, you gotta be willing to dump beer to get there sometimes. Lord knows it's tough, and I've punished myself consuming some pretty not very tasty brews. Most of us have...
There could be many reasons why your beer is to bitter, that are no fault of the kit. One being how long it took you to cool your wort.