I did something similar (USA here). I asked for an automatic debit for a student loan, and got a form to fill out. Among other terms it specified that the len

I did something similar (USA here). I asked for an automatic debit for a student loan, and got a form to fill out. Among other terms it specified that the lender could change the amount taken from my account, unilaterally!!! So I crossed out this part, specified literally the current amount in dollars and cents, and said that any change would require separate written consent from me. And sent it back with a signature. As others pointed out above, if they failed to notice the change, it is their own fault and their own problem, just as they would argue that it was my fault and my problem if I signed without reading all their self-serving, tiny-font, lawyer-crafted language. And they started debiting the account - which has no legal justification other than that piece of paper, therefore they have agreed to the terms. It has not come to a court case, but if they ever withdraw more than the specified amount I'll sue. Would I win? Maybe not, but if not it wouldn't be because of any flaw in my approach. Rather it would be because of the defacto two-tier legal system, where corporations have rights in proportion to their wealth and individuals can't afford to enforce any theoretical rights they supposedly have. I wish I could find the well-written rant on this topic (historical separate court systems for aristocrats and peasants) - Falkvinge maybe.