This sounds like the company my Mother was conned by for a charity, except that was based in Spain. It locked you into four payments for this "Global internet directory" website, each of which was around £2,000. The directory was a plain text list of companies with no SEO, literally just a file four links deep on their own website.
She came to me with it when the first large invoice came in, and I spoke to Trading Standards who were extremely knowledgeable about this company, which changed its name every year. It's possible it's the same one which now has a different country's address.
Trading Standard's advice was simply, "Chuck it in the bin, and with every subsequent letter". I kept the letters, there were about six of them in total before they gave up, all threatening legal action.
This was about ten years ago, so it's sad that it's obviously worked enough times for the model to still be around.