change travel day retroactive (mistake!!)

I‘ve made a mistake!

I‘m going to travel with my son (10). We have got. the 7-days-global-pass.

I wanted to start the journey yesterday, but he became ill. Stomach! 🙈

So I deactivated the first trip, I thougt so: I just deactivated MY pass, I forgot to deactivate the trip on my son‘s pass. So for him the first travel day (1/7), the one out of the country, is already used.

How can I change that? Can somebody from the staff change it for me? Because my son obviosly HASN‘T TRAVELLED YET!
 I saw it by chance, filling in the new trip, because the child finally feels well again and I want to start travelling in three hours…I will get in trouble on the train! Don‘t I?

Thanks a lot.