Lukiluk,
Which one did you order, I'm about to order another one and don't want a faulty one?
You should have Thomann adress the problem with Sire, or even talk to Sire about it in a PM on facebook.
Everyone including Sire Guitars wants a top notch product. They want happy costumors that keep comming back, as do Thomann, as I'm sure you want to be a happy costumor that buys more of their products.
You have a 30 day return guarantee. Don't hesitate!!
The string height issue you have is always a balance between neck relief and height. maybe the neck on the bass was too straight for extremly low action. It has to curve a tiny bit. Get a Feeler gauge like this to get the proper curve on your bass neck, and get these tools if you don't have them already, they will get you a long way:
LASER 2481 FEELER GAUGE SET IMP/METRIC 32 BLADES GUAGE INCLUDES BRASS BLADE | eBay
String Action Gauge Ruler Guide Setup Measuring For Bass Guitar Luthier Tool | eBay
Set of 4 Stainless Steel Understring Radius Gauge - Luthier | eBay
I got these items a while ago and watched some of the online vids like this one:
(EDIT!!! Get a capo too

)