What to do if a website is not responding to my complaints?

[Voelven]

I just looked up Masterseek for you and they have been critizised for inaccurate information before. Plus the company has gone bankrupt several times and the only listed Danish company with this name is listed as being under bankruptcy (it's on the same street, but with a different street number). There are also several Danish articles about Masterseek and its founder online, and at a glance it doesn't entirely positive.

It seems like a bit of a mess, which could explain why they are not responding to you.

You can try sending a letter to the address that is listed for the company Masterseek in Denmark. It's the same as on their webpage, but with housenumber 29 instead of 31.

Or, you can look up who is hosting them and contact the host. I am not sure if what they are doing is illegal, but if it is, then the host is likely to take action.