Booked a trip for my son and had to add my other c...

Booked a trip for my son and had to add my other child too as guest. The day of trip, I get an email that only lists myself and son. Called and was told that the max now is 2 people. What are parents of a disabled child + minor sibling supposed to do when you can't take public transport due to that child's disability. Website should not let you book trips with extra guest if new covid rules only allow max of 2 people. They should also provide an alternative and not just apologize and wish us a good day.