Thank you kindly for your reply. I looked extensively for the live chat, but I could not find it. It would be better to have the support options available in the main support page. This way is hidden in a category.
Turns out that the problem was solved by itself. The dashboard was asking again for a proof of address and now I’ve tried to go to checkout and voilá, the shopify payments are online and running. It was a matter of document verification. But… The warning/error could be better placed, I stumbled upon by chance. I could have gone for days before I found that another proof of address was needed.
Thank you again!