This is an odd one..

Say there is an online service you are interested in. You only need it very briefly, but their only option is a monthly subscription. (I imagine they are probably trying to get people to join and forget..)

So out of other options I set up things so that only 1 payment is ever possible. Service will stop after 1 month automatically, have done it for other cases, should be all fine...

Welp, now they are calling a lawyer because of a 20eur payment. wtf immobilienscout!??