Today, I saw in my banking app that a single cent was added to my account. A bit of Googling tells me this is apparently done sometimes when someone signs up for a service, to validate that a person really exists. I've personally only ever seen the reverse (where you have to pay a cent to validate you own the bank account you're signing up with), but apparently this is a thing too and the description of the transaction is usually a code used to validate.
I checked the IBAN number this money came from, and Googled the company name. The IBAN comes back as Irish, but the company I found with the same name (Worldline Financial Services) doesn't have any offices in Ireland. This looks suspicious. I think somehow a scammer must've gotten a hold on my IBAN and name, because IBAN transactions don't work if you don't have both: I just tried and I can't use the IBAN from my brother + my mother's name, the transaction just won't "validate" and I can't send it.
So, besides wondering what the !?@# I did wrong with my info (I didn't do the obvious ones like open any links and fill anything out, I didn't get any phone calls, didn't use any shady webshops...) I'm wondering what the scam happening here is, and how I best stop it. Would I be better off contacting the customer service for the Worldline Financial Services I found online, and ask them to cancel anything I might've been signed up for(they only seem to have an online form)? Or do I take this immediately to my bank, call them first thing in the morning (they're closed now) and start arranging for a new bank account? Would first thing tomorrow morning be fast enough?