Thank you for your response seek3r.
What do you mean by "numbers stored on their website"?
Sorry. I didn't express myself clearly there. What was meant were the telephone numbers. But it looks like you've already talked to them.
[...]
Also I asked them a lot of questions lately, and they took care of them properly.
That all sounds great and makes a good impression. It certainly doesn't hurt if you find a dealer who will give you advice and support and isn't just concerned about selling as many units as possible.
They told me about pools, however that info I did not get it vetted yet. They said something about antpool and braiins that they should be better with the 2% fee compared to the 4% from ViaBTC.
And ofc paying 2% on fee less is better for ur own pocket/wallet.

At the end you have to see which form of pool is best for you as there are also different reward types (PPS, PPLNS and so on).