So apparently something I did was against their terms of usage…
Since I had a normal profile and normal profile photos, and I had not even been chatting there much, it probably was the image which I added to my profile today to explain why I was planning to stop online dating after this week. I added it as a link to my profile text.
Bad move. Apparently Tinder’s automatic(?) algorithm for abusers has no sense of humor, and they take abusing really seriously.
The link was this image about online dating headache.
Note! Open it at your own risk. It’s a link to Google Image Search for a image about types of headaches, with one described as “online dating”.
tl;dr: Tinder’s support did not offer any explanation nor chance to appeal. They did refund my subscription.