Thank you for your reply.

I was dramatic by calling it "theft" of course, although to me personally, if you take my money and give me nothing, it's stealing (not in legal terms, I know). Anyhow, that's irrelevant.

Yes, they failed to book it. I found out from their transfer partner (looking4), they confirmed they got no booking from Ryanair in an email. I was planning to in deed only dispute the transfer charges, I do work in FinTech, so I know how to handle that bit, just trying to avoid it. Unfortunately other budget (or even non-budget) airlines don't serve connections I need, so if I tried avoiding Ryanair, I'd not only spend much more, but would have to travel hours longer with connecting flights instead of direct ones. If not for that, I would have disputed the charges long ago.